All tools
242 tools, each answering a single question from a named data source.
Home & Property
Questions about a specific building or plot, or the systems that serve it.
What Soil Type Is My Property?
Enter an address and get the soil series, texture, drainage, pH and depth to water table for that exact spot.
USDA NRCS Soil Data Access (SSURGO)
Water Softener Size Calculator
Enter your water hardness and household size and get the grains removed per day, the capacity that implies, and how often a given unit would regenerate.
Penn State Extension and NDSU Extension water softening publications
Septic Tank Size Calculator
Enter the number of bedrooms and get the minimum tank capacity EPA's design manual reports for one- and two-family homes, with the table and page it comes from.
USEPA Onsite Wastewater Treatment Systems Manual, Table 4-13
How Many ADA Parking Spaces Are Required?
Enter the total spaces in a parking lot and get the minimum accessible and van-accessible count from the 2010 ADA Standards, with the rule and the arithmetic.
2010 ADA Standards for Accessible Design, §208.2 and §502
Pool Salt Calculator
Enter your pool's volume, current salt reading and target level and get the pounds of salt to add — or how much water to replace if the salt is too high.
Mass-balance formula, cross-checked against Hayward's AquaRite manual salt table
Pool Shock Calculator
Enter your pool's volume, current and target free chlorine and the product you use, and get how much shock to add — from a state health department's published dose table.
Indiana Department of Health pool chemical adjustment guide (adapted from the NSPF handbook)
Muriatic Acid Pool Calculator
Enter your pool's volume and current and target total alkalinity and get how much 31.4% muriatic acid to add, and how many separate additions the one-quart limit means.
Indiana Department of Health pool chemical adjustment guide (adapted from the NSPF handbook)
Pool Alkalinity Calculator
Enter your pool's volume and current and target total alkalinity and get how much baking soda, soda ash or sesquicarbonate raises it — or acid lowers it — product by product.
Indiana Department of Health pool chemical adjustment guide (adapted from the NSPF handbook)
Pool Stabilizer Calculator
Enter your pool's volume and current and target stabilizer (cyanuric acid) and get how much to add — or what share of the water to replace if it is too high.
Indiana Department of Health pool chemical adjustment guide (adapted from the NSPF handbook)
Pool Pump Run Time Calculator
Enter your pool's volume and the flow through the filter and get how long one turnover takes and how many hours a day the pump must run — with the CDC model code's maximum turnover times for public pools.
CDC Model Aquatic Health Code 2023, section 4.7.1.10 and Table 4.7.1.10
Pool Heater Size Calculator
Enter your pool's size, the temperature you want and the coldest month's average and get the approximate gas heater output in Btu/hour, by the U.S. Department of Energy's formula.
U.S. Department of Energy, Energy Saver: Gas Pool Heaters (sizing formula)
R22 PT Chart
Enter a temperature to get R-22's saturation pressure, or a gauge reading to get its saturation temperature — °F or °C, psig, psia, kPa or bar — from NIST data, −40°F to 150°F.
NIST Chemistry WebBook (SRD 69), R22 saturation properties
Well Pump Size Calculator
Count your bathrooms and fixtures and get the pump capacity in gallons per minute by the Water Systems Council's two methods — fixture count and seven-minute peak demand — checked against your well's yield.
Water Systems Council wellcare sheet, Sizing a Well Pump
Oil Tank Chart
Enter the inches of oil on your dipstick and get the gallons left in a 275 or 330 gallon oval tank, a 500, 550 or 1000 gallon round tank, or your own tank, with the full inch-by-inch chart.
Tank geometry (circular-segment areas) × rated capacity; pickhvac.com standard tank sizes
Bradford White Water Heater Age
Type the serial number from a Bradford White water heater and get the month and year it was made and its age, using Bradford White's own date code.
Bradford White 'Determining The Age Of A Water Heater' bulletin
Water Heater Age by Serial Number
Pick the brand, type the serial number from the rating plate, and get when an A. O. Smith, Rheem or Bradford White water heater was made and how old it is.
Makers' published serial formats: A. O. Smith Service and Warranty Guide, Rheem, Bradford White
Firewood Calculator
Enter the length, height and depth of a woodpile and get its volume in cords (128 cubic feet), face cords and cubic metres, plus the price per full cord.
NIST Handbook 130 cord definition (128 cubic feet, ranked and well stowed)
Mini Split Size Calculator
Enter each room's size, sun, occupants and whether it's a kitchen and get the cooling BTU/h per zone and in total from ENERGY STAR's sizing chart and adjustments.
ENERGY STAR room air conditioner sizing chart
Well Volume Calculator
Enter the casing diameter, well depth and static water level and get the gallons standing in the well, gallons per foot, and the bleach for a chlorine concentration you choose.
Cylinder volume (231 in³ per US gallon)
Workplace & Safety
What a published standard or regulation actually requires.
OSHA Soil Classification
Answer the questions OSHA's criteria ask and get the soil type — A, B, C or stable rock — with the clause that decides it.
OSHA 29 CFR 1926 Subpart P, Appendix A
When Does My Propane Tank Expire?
Enter the date stamped on your propane cylinder's collar, and any requalification mark, and get the month it next needs requalifying under 49 CFR 180.209.
49 CFR 180.209(e) and (g), marks per 49 CFR 180.213
When Does My Fire Extinguisher Expire?
Pick the extinguisher type and enter its manufacture or last test date to get the next hydrostatic test, and the 6-year maintenance where it applies, from OSHA 1910.157 Table L-1.
OSHA 29 CFR 1910.157(e) and (f), Table L-1
How Many Smoke Detectors Do I Need?
Enter your bedrooms, sleeping areas and levels and get the minimum number of smoke alarms the International Residential Code requires, location by location, for the 2024 or 2021 edition.
2024 IRC Section R310.3 / 2021 IRC Section R314.3
Playground Mulch Calculator
Enter the play area and the surfacing — wood chips, wood mulch, rubber, pea gravel or sand — and get the cubic yards to install at CPSC's minimum depth, allowing for compression.
U.S. CPSC Public Playground Safety Handbook, Table 2 and §2.4.2.2
Occupancy Load Calculator
Pick the function of each space and enter its floor area and get the occupant load from IBC 2021 Table 1004.5, space by space and in total.
2021 IBC Section 1004.5 and Table 1004.5
Construction & DIY
Measurements, framing and material questions with a concrete numeric or code answer.
Roof Pitch Calculator
Enter the rise and run and get the pitch as x-in-12, the angle, the slope percentage and the rafter length — plus which roof coverings the IRC allows at that slope.
Geometry, and the 2021 International Residential Code, Chapter 9
Rebar Size Chart
Pick a bar size and get its diameter, cross-sectional area and weight per foot in US and metric units, from a state DOT's published reinforcement table.
Illinois DOT Standard 001001-02, Areas of Reinforcement Bars
Egress Window Calculator
Enter a window's clear opening and sill height and see which IRC R310 egress minimums it meets — area, width, height, sill and window well — with the section for each.
2021 International Residential Code, Section R310
ADA Ramp Calculator
Enter the rise and get the minimum ramp length, the number of runs and landings, and whether handrails are required under the 2010 ADA Standards §405.
2010 ADA Standards for Accessible Design, §303 and §405
NPT Tap Drill Size
Pick a pipe thread size from 1/16 to 3 inch and get the tap drill for NPT — with its decimal and millimetre size and the NPS straight-thread drill — from a tap maker's published chart.
Sowa Tool tap & drill chart, taper pipe taps (NPT) and straight pipe taps (NPS)
Sine Bar Calculator
Enter a sine bar's length and an angle in degrees, minutes and seconds to get the gauge block stack height — or enter the stacks to get the angle. Inches or millimetres.
Sine bar formula, Manufacturing Processes 4-5 (open textbook, CC BY)
Asphalt Tonnage Calculator
Enter the area and compacted thickness and get the tons of hot-mix asphalt, using the 110 lb per square yard per inch rule of thumb or a state DOT's spread rate.
Asphalt magazine (Asphalt Institute), Equation 1 and the 110 lb/sq yd/in spread rate
Asphalt Millings Calculator
Enter the area and compacted depth and get the cubic yards of asphalt millings and a tons range from FHWA's published weight for reclaimed asphalt — or your supplier's own weight.
FHWA-RD-97-148, Reclaimed Asphalt Pavement, Table 13-2
Shower Floor Slope Calculator
Enter the distance from the drain to the farthest edge of the shower floor and get how high that edge must sit under the 2021 IRC's ¼ to ½ inch per foot rule — and check a planned slope and curb.
2021 International Residential Code, Section P2709.1
Door Handing Chart
Answer three questions — which side you're on, where the hinges are, which way the door swings — and get the door hand: LH, RH, LHR or RHR, by Allegion's published handing rule.
Allegion Steelcraft handing procedures and Schlage handing instruction
Chainsaw File Size Chart
Pick your chain's pitch or the number stamped on its drive link and get the round file size, filing angles and depth-gauge setting from Oregon's published chart, with STIHL's own figure alongside.
Oregon saw chain filing and grinding angles chart (catalog p. FOR 149); STIHL saw chain files
Deck Joist Span Calculator
Pick the lumber species, joist size, spacing and load and get the maximum deck joist span from IRC Table R507.6, plus the cantilever for your back span and a check of your own span.
IRC Table R507.6 Maximum Deck Joist Spans (2021 and 2024, identical); AWC DCA 6-2015 Table 2
Hip Roof Calculator
Enter the building's length, width, pitch and overhang and get the hip roof's area in squares, the ridge length and the common and hip rafter lengths.
Roof geometry by pitch per 12 in of run; hip rafter method from Griffith, Carpentry §23
Gutter Coil Calculator
Turn a gutter coil's weight into feet, or feet of gutter into pounds of coil, for 11-3/4, 11-7/8 and 15 inch aluminum, copper and Galvalume coil, from a supplier's published yield chart.
Gutter Supply "Coil Yields" spec sheet (lb per ft and ft per lb)
Pressure Washer Nozzle Calculator
Enter your pressure washer's GPM and PSI and get the nozzle orifice size, the nearest standard sizes and the pressure each would give, from a pump maker's nozzle chart.
General Pump Nozzle Chart (2021): GPM by nozzle size and PSI
Lumber Cost Calculator
Enter a cut list and the prices you were quoted — per piece, linear foot, board foot or MBF — and get the board feet, cost per board foot and total with waste and tax.
NIST Handbook 130 (2026) board foot definition and Table 1 lumber sizes
Log Volume Calculator
Enter a log's small-end diameter and length and get its wood volume in board feet by the Doyle and International 1/4-inch rules, plus cubic feet and cubic metres.
Briggs (1994), Univ. of Washington: log rule formulas and Appendix 3 tables
Table Top Epoxy Calculator
Enter a tabletop's size, coat thickness and number of coats and get the gallons of epoxy to mix, with edges, an allowance for drips and the resin/hardener split.
Volume arithmetic (231 in³/gal, NIST HB 44); cross-checked to TotalBoat's 12.8 sq ft/gal at 1/8 in
Drawer Size Calculator
Enter the cabinet opening and get the drawer box width, height and length for Blum TANDEM 563H undermount or Accuride 3832EC side-mount slides, from each maker's clearances.
Blum TANDEM 563H spec sheet; Accuride 3832EC quick reference
Gridfinity Calculator
Enter a drawer's inside size and get how many 42 mm Gridfinity units fit, the leftover margin, the tallest bin in 7 mm units, and how to split the baseplate for your print bed.
Gridfinity Design Reference v5 (gridfinity.xyz): 42 mm grid, 7 mm height unit
Stair Stringer Calculator
Enter the total rise and tread depth and get the risers, riser height, total run, stringer length, angle and throat, checked against the American Wood Council's DCA 6 deck stair rules.
American Wood Council DCA 6 (2015 IRC): stair requirements, Figures 27–30
Resin Volume Calculator
Enter a mold's shape and inside size, or the water it holds, and get the resin to mix in ml and fl oz, its weight, and the part A / part B split.
Solid geometry; specific gravities from Smooth-On and West System technical data sheets
STL Volume Calculator
Open a binary or ASCII STL file in your browser and get its volume, bounding box, a closed-mesh check and the solid weight in PLA, PETG, ASA or your own material.
Signed-tetrahedron volume (Zhang & Chen 2001); Prusament filament densities
Deck Beam Span Chart
Pick the species, load, joist span and joist overhang and get the maximum deck beam span for every built-up beam size from IRC Table R507.5.
IRC 2024 Tables R507.5(1)–(4) Maximum Deck Beam Span
Baseboard Calculator
Enter the room's walls, doorways and stock length and get the linear feet of baseboard, the number of pieces to buy with waste, and the cost.
Perimeter arithmetic (walls − openings, plus waste allowance)
How Many Screws per Sheet of Drywall
Pick the sheet size, wall or ceiling and framing spacing and get the screw count per sheet and for the job at the IRC's maximum fastener spacing.
IRC 2024 Table R702.3.5 (maximum fastener spacing for gypsum board)
Roller Chain Size Chart
Measure the pitch, roller diameter and inner width of a chain and identify its ANSI number (25 to 240), with the full dimension chart in inches and millimetres.
Tsubaki ANSI roller chain dimension table (RS25–RS240)
Crown Molding Angle Chart
Enter the corner angle and the molding's spring angle and get the miter and bevel settings for cutting crown flat on a compound miter saw, with a full angle chart.
Compound-miter formulas for crown molding (spring angle and wall angle)
Tile Calculator
Enter the area, tile size and grout joint and get how many tiles and boxes to buy with your waste allowance, and the cost.
Area arithmetic including the grout joint
Linear Foot Calculator
Convert square feet to linear feet of boards by coverage width, add up pieces into total linear feet, or turn linear feet back into square feet.
Length and area arithmetic
Board and Batten Calculator
Enter the wall width, batten size and the gap or count you want and get exact equal spacing, each batten's position and the linear feet to buy.
Equal-spacing layout arithmetic
Rafter Length Calculator
Enter the span, pitch, overhang and ridge board and get the common rafter length in feet and inches, the rise, the roof angle and the stock length that covers it.
Griffith, Carpentry §17 (common rafter length)
Roof Truss Calculator
Enter the building length, spacing, span and pitch and get how many trusses you need, the closing space, top chord length and rise.
Truss count and outline geometry; IRC 2021 R802.10
Sonotube Concrete Calculator
Enter the tube diameter, depth and number of tubes and get the concrete in cubic yards and the bags of 40, 50, 60, 80 or 90 lb mix to buy.
QUIKRETE Concrete Mix 1101 yields; QUIK-Tube bag table
Deck Railing Spindle Spacing Calculator
Enter the space between posts and the spindle width and get the fewest spindles that keep every gap under the IRC's 4-inch sphere, with exact spacing and positions.
2021 IRC R312.1.3 guard opening limits
Wainscoting Calculator
Enter the walls, openings and wainscot height and get the area, how many panel sheets to buy when cut into strips, the trim pieces, and an even panel layout for any wall.
Sheet-yield and layout arithmetic
Countertop Square Footage Calculator
Enter each countertop section, the backsplash height and any sink cut-outs and get the gross and net square footage and the cost at a price per square foot.
Area arithmetic
Drop Ceiling Calculator
Enter the room size and panel size and get the panels, main beams, cross tees, wall molding and hanger wires, with balanced border panels laid out the way Armstrong's guide does.
Armstrong suspended ceiling installation guide
Gambrel Roof Calculator
Enter the span, the break point and the two pitches and get both rafter lengths, the rise at the break and ridge, the roof area in squares and the gable end area.
Right-triangle roof geometry
Caulking Calculator
Enter the joint length, width and depth and get the sealant volume and how many 10.1 oz cartridges, sausages or gallons to buy, with a waste factor.
Tremco sealant estimating method
Wallpaper Calculator
Enter your walls, height, roll size and pattern repeat and get the drops you need, full drops per roll and the number of rolls to buy, using a wallpaper maker's method.
James Dunlop wallpaper calculation method
Stucco Calculator
Enter the wall area, openings and the thickness of each coat and get how many 80 lb bags of stucco to buy, coat by coat, from Quikrete's published yields.
QUIKRETE stucco data sheets (1139, 1201)
Shiplap Calculator
Enter your walls, the board's exposed face and length and get how many shiplap boards to buy, counted row by row and by area, with linear feet and cost.
Course and area arithmetic
Concrete Step Calculator
Enter the number of steps, rise, run, width and top platform and get the concrete for solid steps in cubic yards and the bags of mix to buy.
Stair profile geometry; QUIKRETE Concrete Mix 1101 yields
Block Fill Calculator
Enter the wall size, block width and which cells are grouted and get the grout in cubic feet and yards and the bags of preblended grout, from the CMHA (NCMA) estimating tables.
CMHA TEK 04-02A grout volume tables
Self-Leveling Concrete Calculator
Enter the floor area and average thickness and get how many bags of self-leveling underlayment to buy, from Quikrete's published yield, or any product's yield.
QUIKRETE Self-Leveling Floor Resurfacer (1249-50) data sheet
Paint Calculator
Enter the room size, doors, windows and coats and get how many gallons and quarts of paint to buy.
Wall area arithmetic; Behr published coverage (250-400 sq ft per gallon)
Concrete Calculator
Enter a slab, footing or column size and get the concrete in cubic yards and the number of 40, 50, 60, 80 or 90 lb bags.
Volume arithmetic; QUIKRETE No. 1101 bag yields
Square Feet Calculator
Add rectangles, circles, triangles and L-shaped areas in any unit and get the total square feet, square metres and acres.
Area geometry; NIST Handbook 44 unit definitions
Flooring Calculator
Enter the floor area, waste allowance and square feet per box and get how many boxes, planks and the cost.
Area arithmetic
Fence Calculator
Enter the fence length, post spacing and gates and get the posts, rails, pickets and concrete bags to buy.
Layout arithmetic; QUIKRETE No. 1101 bag yields
Farm & Livestock
Breeding, feeding and field questions answered from extension and agency publications.
Cow Gestation Calculator
Enter a breeding or AI date and get the calving date at the traditional 283 days and at the shorter average a 101,787-mating Angus study found — with the window most calves arrive in.
K-State Extension Beef Tips (July 2026), gestation length in modern beef cattle
Sheep Gestation Calculator
Enter a breeding date — or the dates a ram or crayon colour was on — and get the lambing window from the Merck Veterinary Manual's 144–150-day normal gestation.
Merck Veterinary Manual (normal sheep gestation 144–150 days)
Honey Yield Calculator
Weigh your supers before and after extraction and get the honey harvested in pounds, kilograms, gallons and full jars, with yield per hive against USDA's U.S. average.
National Honey Board (12 lb per gallon); USDA NASS Honey, March 2026
Honey Production Calculator
Enter your colonies and state to estimate honey production in pounds and its value, from USDA's 2025 yield per colony and honey prices — or your own figures.
USDA NASS Honey (March 2026): 2025 yield and price by state
Horse Calorie Calculator
Enter a horse's weight and workload and get its daily digestible energy need in Mcal and kcal from the NRC (2007) equations, with an optional hay and grain check.
Merck Veterinary Manual (2026), NRC Nutrient Requirements of Horses (2007)
Horse Blanket Size Chart
Enter your horse's chest-to-rump measurement and get the blanket size in US inches, UK feet and centimetres, plus the Euro back-seam size, with the full chart.
WeatherBeeta horse blanket size guide
Horse Feed Cost Calculator
Enter hay and grain amounts and your bale and bag prices and get the daily, monthly and yearly cost to feed a horse, plus bales and bags used per month.
Owner's own prices; Merck Veterinary Manual forage guideline
Horse Color Calculator
Enter the sire's and dam's coat color test results and get the odds of each foal color, from chestnut, bay and black to palomino, buckskin, cremello and grullo.
UC Davis Veterinary Genetics Laboratory gene pages (Extension, Agouti, Cream, Dun, Gray)
Goat Gestation Calculator
Enter a breeding date — or the dates a buck ran with the does — and get the kidding window from the Merck Veterinary Manual's 145–155-day goat gestation.
Merck Veterinary Manual (goat gestation 145–155 days, average 150)
Pig Gestation Calculator
Enter a breeding date and get the farrowing date at 114 days and the 113–116-day farrowing window, plus a gestation chart of key dates.
Merck Veterinary Manual (pig 114 days); Pork Industry Handbook (113–116 days)
Grain Bin Calculator
Enter the bin diameter and grain depth, with a peak or drawn-down cone, and get standard bushels using the Iowa Department of Agriculture's grain measuring method.
Iowa Dept. of Agriculture grain measuring guidelines
Horse Gestation Calculator
Enter the breeding date and get the mare's expected foaling window, the normal 320–370 day range, the premature cutoff and the 11-month date, from university extension figures.
University of Nebraska Extension G1874, The Foaling Mare
Health & Everyday
Everyday measurement questions answered from published specifications and agency formulas.
Capsule Size Chart
Pick a capsule size, 000 to 5, and get its volume, how many mg it holds at your powder's density, and its length and diameter — or enter a fill and get the smallest size that holds it.
Capsugel Coni-Snap hard gelatin capsule specifications
Motorcycle Wind Chill Chart
Enter the air temperature and your riding speed and get the wind chill by the National Weather Service formula, with a full chart from 10 to 80 mph.
National Weather Service wind chill formula (2001)
Christmas Tree Light Calculator
Enter your tree's height and the lights per set and get how many lights and sets to buy, by the 100-lights-per-foot rule, plus how many incandescent sets CPSC says can be joined.
Published lights-per-foot rule of thumb; U.S. CPSC holiday safety guidance
Aquarium Gravel Calculator
Enter your tank's inside length and width and the bed depth you want and get the pounds of gravel or sand and the number of bags, using CaribSea's published formula and substrate weights.
CaribSea FAQ: length x width x depth / 1,728 x substrate density
Aquarium Volume Calculator
Enter a fish tank's inside dimensions — rectangle, bow front, cylinder, hexagon or corner — and get the water volume in gallons and litres after substrate and rim gap, plus its weight.
Volume geometry; NIST HB 44 gallon/litre; USGS 8.34 lb per gallon
Betta Tank Size Calculator
Enter your betta's tank dimensions or volume and see its real water volume, compared with the RSPCA's 10-litre minimum and 20-litre ideal and a 2024 welfare study's figure.
RSPCA Australia betta care (2024); Clark-Shen et al. 2024, Animal Welfare
Cichlid Stocking Calculator
List the cichlids you plan to keep and see their total adult length from FishBase against a published stocking guideline for your tank's volume.
Practical Fishkeeping stocking guideline; FishBase maximum lengths
Trolling Motor Size Calculator
Enter your fully loaded boat weight and get the minimum trolling motor thrust, the 12/24/36 V battery setup, and the shaft length for your bow or transom height.
Minn Kota Motor Size selection guide (Rev. 8.21.2020) and buying guide
Knitting Needle Size Chart
Convert a knitting needle size between millimetres and US numbers using the Craft Yarn Council standard, with the full chart and the sizes that share a US number.
Craft Yarn Council standard — Hooks & Needles
Dilution Ratio Calculator
Enter a 1:N ratio and how much mix you want, or how much product you have, and get exactly how much product and water to measure.
Parts arithmetic; NIST US volume units
Alcohol Dilution Calculator
Enter the starting and target strength in ABV or proof and how much spirit you have (or want) and get exactly how much water to add.
C1V1 = C2V2; proof per 26 U.S.C. 5002
Time-Lapse Photography Calculator
Enter how long you'll shoot, your interval and frame rate and get the number of photos, the finished clip length, the speed-up and the storage — or the interval for a clip length you want.
Interval and frame-rate arithmetic
Grams to Cups
Convert grams to cups, or cups to grams, for over 100 baking and cooking ingredients, each with its own published weight.
King Arthur Baking Ingredient Weight Chart
Oven Temperature Conversion
Convert oven temperatures between Fahrenheit, Celsius and gas mark, with the full conversion chart.
C = (F - 32) x 5/9; gas mark scale
Recipe Converter
Paste a recipe's ingredient list, choose new servings and get every quantity scaled, in kitchen fractions.
Proportional scaling
Shoe Size Conversion
Convert adult shoe sizes between US men's, US women's, UK, EU and Mondopoint, or find your size from foot length.
ISO/TS 19407 size equations (via Wikipedia, Shoe size)
Ring Size Chart
Convert ring sizes between US, UK, ISO (EU), Swiss and German systems, or get your size from a ring's diameter or finger circumference.
ISO 8653; US and BS 6820 ring size relations (via Wikipedia, Ring size)
Sleep Calculator
Enter when you need to wake up and get bedtimes that fit whole 90-minute sleep cycles, or wake-up times if you go to bed now.
NINDS sleep cycle description; CDC sleep duration
Work & Business
Pay, cost and logistics arithmetic, with the published rules and figures behind it.
Tip Pool Calculator
Enter the night's pooled tips and each person's hours (or hours and points) and get every share to the cent, adding up to the pool exactly.
Proportional split in whole cents; U.S. DOL WHD Fact Sheet #15 for tip-pool rules context
Truck Cost Per Mile Calculator
Enter a period's truck costs, fuel and miles and get your cost per mile and per loaded mile, split into fixed, variable and fuel, next to ATRI's industry average.
Cost ÷ miles; ATRI 2026 Operational Costs of Trucking benchmark ($2.336/mile in 2025)
Freight Linear Feet Calculator
Enter the pallet count, pallet size and whether they stack, and get the linear feet of trailer floor they take — loaded straight and turned — in a 101-inch-wide trailer or your own.
Pallet floor geometry; Utility Trailer 53' dry van inside width (101 in)
Cash Drawer Calculator
Count the drawer by bills, rolls and coins and get the total, the deposit that leaves your starting float, which notes and coins to pull, and whether it is over or short.
Whole-cent arithmetic; U.S. Mint coin roll contents
Boat Fuel Cost Calculator
Enter your boat's fuel burn and engine hours, or distance and speed, plus the fuel price, and get the trip's fuel, cost, cost per hour and mile, and rule-of-thirds fuel to carry.
Owner's burn rate and price; NC Sea Grant full-throttle estimate and rule of thirds
PTO Accrual Calculator
Enter your PTO policy and pay schedule and get the hours you earn each paycheck, per hour worked and per year, with a balance projection and cap.
Accrual arithmetic; U.S. DOL Vacation Leave guidance
Real Estate Commission Calculator
Enter the sale price, rate or flat fee and the splits and get the total commission, each side's share, the agent's cut and the seller's net.
Commission split arithmetic
Cake Pricing Calculator
Enter what you paid for each ingredient, how much the recipe uses, your hours and overhead, and get the cake's true cost, a price at your markup or margin, and the price per serving.
Recipe costing arithmetic
Lawn Mowing Cost Calculator
Enter the lawn size, mower width, speed and your rates and get the time each mow takes and a price per visit and per month built from your own costs.
Field-capacity formula (width × speed × efficiency ÷ 8.25)
Break-Even ROAS Calculator
Enter your price and per-order costs, or your margin, and get the ROAS and ACoS where ads break even, the ROAS for a target profit, and what your current ROAS earns per ad dollar.
Break-even arithmetic (1 ÷ margin)
Paper Weight Conversion Calculator
Convert paper basis weight in pounds to gsm and back for bond, text, cover, index, bristol and tag, and see the same paper's weight in every grade.
Sylvamo basis weight formula and basic sizes
Moving Box Calculator
Enter how many small, medium and large boxes you plan to pack and get the total volume for the truck, the box cost and the tape.
Box volume arithmetic
Sports & Outdoors
Gear sizing and outdoor questions answered from manufacturers' published charts and guides.
Ski Size Chart
Enter height, and a child's weight, and get the suggested ski length range in cm from Nordica's adult and junior charts, plus which end of the range to lean toward.
Nordica Ski Sizer (adult and child charts)
Ski Boot Size Chart
Convert a Mondopoint ski boot size to US men's, women's, kids', EU and UK sizes, or the other way round, with Nordica's standard and performance fit sizes.
Nordica Ski Boot Sizing Chart (men's, women's and junior)
Snowboard Size Chart
Enter your weight and boot size and get the snowboard length from Jones's adult and kids charts, the middle size when you fall in two ranges, and the minimum waist width if you need a wide board.
Jones Snowboards size guide (weight charts and wide-board chart)
Scuba Weight Calculator
Enter your body weight, suit, water and tank and get a starting dive weight from PADI's and DAN's guidelines, with each adjustment listed.
PADI and DAN weighting guidelines; Scuba Diving magazine buoyancy article
What Year Is My Mercury Outboard?
Type the two-letter year code from your Mercury outboard's serial number decal and get the year it was made, using the table in Mercury's own manual.
Mercury Marine owner's manual 8M0165094, Model Year Production Code
Go Kart Gear Ratio Calculator
Enter clutch and axle sprocket teeth, tyre size and engine RPM and get the gear ratio, theoretical top speed and a gear ratio chart, with jackshaft support.
Chain-drive gear ratio and speed formula (CSG Network kart speed calculator)
Fishing Reel Line Capacity Calculator
Enter the reel's rated capacity and your line's diameter and get how many yards or metres of that line the spool holds, including braid over mono backing.
Spool capacity ∝ line diameter² × length (cylinder volume)
BMX Gear Ratio Calculator
Enter the front sprocket, rear driver and wheel size and get the gear ratio, gear inches, rollout, development and speed at your cadence, with a gear chart.
Sheldon Brown gear inches and development
Maps & Location
Where a point is — city, county, state, country, ZIP code, elevation — from public datasets, for your location or any address.
What Is My Elevation?
Use your current location or type an address and get the ground elevation above sea level in feet and metres, from USGS 3DEP and the Copernicus 90 m model side by side.
USGS 3D Elevation Program (EPQS) and Copernicus DEM GLO-90
What County Am I In?
Use your current location or type an address and get the county (or parish, borough or municipio), state and FIPS codes from the 2020 Census, with a warning when you are near a county line.
FCC Area API (2020 Census blocks)
What State Am I In?
Use your current location or type an address and get the US state or territory you are in from the 2020 Census, with a warning when you are close to a state line.
FCC Area API (2020 Census blocks)
What Country Am I In?
Use your device's location or a typed place and get the country it falls in, with its ISO code and region, from OpenStreetMap data — not from your IP address.
OpenStreetMap via the Photon geocoder
What City Am I In?
Use your current location or type an address and get the city or town you are in — and, in the US, whether you are inside its legal city limits or in an unincorporated area, from Census boundaries.
US Census Bureau TIGERweb place boundaries; OpenStreetMap via Photon
What ZIP Code Am I In?
Use your current location or type an address and get the ZIP code area you are in, drawn on a map, with its population, median household income and home value from the Census Bureau.
Census 2020 ZIP Code Tabulation Areas (TIGERweb); ACS 2019–2023 5-year estimates
Elevation Finder
Click up to 50 points on a map (or paste coordinates) and get the ground elevation of each in feet and metres, with the height difference between them, from the Copernicus 90 m model.
Copernicus DEM GLO-90 via Open-Meteo
Distance & Measurement
Straight-line and road distances, areas, radii and travel-time zones, measured on the WGS84 ellipsoid or over OpenStreetMap roads.
As the Crow Flies Distance Calculator
Enter two places and get the straight-line distance between them in miles, kilometres and nautical miles, measured on the WGS84 ellipsoid, with the compass bearing and the route on a map.
Vincenty (1975) geodesic on the WGS84 ellipsoid
Halfway Point Between Two Cities Calculator
Enter two cities or addresses and get the exact halfway point between them — or any split you choose — with the nearest named place and the distance from each side.
Vincenty (1975) geodesic midpoint on WGS84, OpenStreetMap place names
Radius Map
Draw one or more true-distance circles in miles or kilometres around any address on a map, see the area each covers, and check whether another place falls inside.
Geodesic circles on WGS84 over OpenStreetMap tiles
Distance to Horizon Calculator
Enter your eye height and get how far away the horizon is, with and without standard atmospheric refraction, plus how far you can see a tall object and how much of it the curve hides.
Spherical-Earth horizon formula d = √(2Rh + h²), refraction R′ = 7R/6 (A. T. Young)
Distance Between Two Places
Enter any two addresses or places and get both the straight-line distance and the driving, cycling or walking distance and time, drawn on a map.
Vincenty on WGS84; OSRM routing over OpenStreetMap (FOSSGIS)
Distance Between Cities
Pick any two US cities or towns from the Census list of 32,000 places and get the miles between them in a straight line and by road, plus the distance to the largest US cities.
Census 2024 Gazetteer place points; OSRM driving routes
Distance Between ZIP Codes
Enter two ZIP codes for the straight-line and driving distance between them, or one ZIP and a list of thousands to get every distance as a CSV.
Census 2024 Gazetteer ZCTA points; OSRM driving routes
Multi-Stop Distance Calculator
List up to 25 stops and get the total driving, cycling or walking distance and time with every leg — in your order or reordered for the shortest trip, one way or round trip.
OSRM route and trip services over OpenStreetMap (FOSSGIS)
Distance Matrix Calculator
List up to 20 places and get a table of the road distance and travel time between every pair, or the straight-line distances, ready to download as CSV.
OSRM table service over OpenStreetMap (FOSSGIS); Vincenty
Map Area Calculator
Click the corners of a field, lot or any shape on a map and get its area in acres, square feet, hectares and square miles, plus the perimeter, measured on the WGS84 ellipsoid.
Ellipsoidal polygon area (Chamberlain & Duquette; Snyder authalic latitude)
Drive Time Map
Pick a starting point and see the area you can reach in 10, 20 or 30 minutes by car, bike or on foot, with the size of each zone and, in the US, how many people live inside it.
Valhalla isochrones over OpenStreetMap (FOSSGIS); Census tracts
Elevation Profile
Draw a path on a map or route between two places and get its elevation profile chart with total climb and descent, highest and lowest points and the steepest grade.
Copernicus DEM GLO-90 via Open-Meteo; OSRM routes
Coordinates & Geocoding
Addresses to coordinates and back, coordinate format conversions, bearings, antipodes and centre points.
Random Location Generator
Generate truly uniform random coordinates anywhere on Earth, inside a box, or within a radius of a place — with an option to skip open sea and the points shown on a map.
Uniform sphere point picking (MathWorld) with Web Crypto randomness
Address to Coordinates
Turn one address or a whole list into latitude and longitude, with the matched place name, and download the results as CSV.
OpenStreetMap via the Photon geocoder
Coordinates to Address
Enter latitude and longitude (any format) or click a map and get the nearest street address, plus the ground elevation and the local time zone at that point.
OpenStreetMap via Photon; Copernicus DEM via Open-Meteo
Coordinates to City
Paste one coordinate pair or a list of up to 200 and get the city, county, state and country for each, ready to download as CSV.
OpenStreetMap via the Photon reverse geocoder
Coordinates to Country
Paste one coordinate pair or a list of up to 200 and get the country and its ISO 3166-1 alpha-2 code for each, with points at sea flagged rather than guessed.
OpenStreetMap via the Photon reverse geocoder
Coordinates to State
Paste one coordinate pair or a list of up to 200 US points and get the state, two-letter code, county and FIPS codes for each from 2020 Census blocks, ready to download as CSV.
FCC Area API (2020 Census blocks)
Latitude and Longitude Finder
Click anywhere on a map, search an address or use your location and get the exact latitude and longitude in decimal degrees, degrees-minutes-seconds and decimal minutes, ready to copy.
OpenStreetMap tiles and Photon geocoder; WGS84 coordinates
Plot Coordinates on Map
Paste a list of coordinates in any common format, with optional labels, and see them as pins on a map — joined as a route if you like — then download as GeoJSON, KML or CSV.
Your coordinates on OpenStreetMap tiles
GPS Coordinate Converter
Paste a coordinate in any format — decimal degrees, DMS, decimal minutes, UTM, MGRS, Plus Code or geohash — and get it in every other format, one at a time or a whole list to CSV.
WGS84 conversions: Karney (2011) UTM, NGA MGRS, Open Location Code, geohash
UTM to Lat Long Converter
Enter a UTM zone, hemisphere, easting and northing and get latitude and longitude on WGS84 — or convert the other way, or a whole list at once.
Transverse Mercator by Krüger's series (Karney 2011), WGS84
Antipode Finder
Find the exact point on the opposite side of the Earth from any address or your location, whether it is land or ocean, and see where land lies opposite land on a world map.
Antipode on WGS84; Copernicus DEM via Open-Meteo; Natural Earth land
Bearing Calculator
Enter two places or click a map and get the true and magnetic bearing from one to the other, the bearing on arrival, the back bearing and the constant-heading rhumb line.
Vincenty inverse on WGS84; NOAA/BGS World Magnetic Model 2025
Geographic Center Finder
Find the geographic midpoint and the centre of minimum distance of any set of places, optionally weighted, or the area-weighted centre of any US state or country.
Spherical centroid and geometric median; Census and Natural Earth boundaries
Dig Through the Earth Map
Pick where you start digging and see where a tunnel straight down would come out, how long it is, which layers of the Earth it passes and how long a fall through it would take.
WGS84 ellipsoid normal; PREM Earth model (Dziewonski & Anderson 1981)
Map Makers & GIS Files
Make, colour, annotate and export maps, and open KML, GPX, GeoJSON and CSV files in the browser.
Google Maps Embed Code Generator
Make the iframe code to put a Google Map on your website — a place, search, directions, view or Street View — with size, responsive layout and accessibility title set for you.
Google Maps Embed API parameters (Google documentation)
Draw on Map
Draw freehand, lines, shapes and markers on a real map, see each line's length and each shape's area, label them and download the drawing as GeoJSON, KML or GPX.
OpenStreetMap tiles; geodesic lengths and ellipsoidal areas
Map Legend Maker
Build a legend for any map — colours, area, point, pin and line symbols, labels, columns and a title — and download it as a PNG (transparent if you like) or SVG.
Made in your browser (SVG)
Color a Map
Click to colour US states, world countries or one continent, add a title and legend, or paste a list or numbers to shade them, then download the map as PNG, SVG or PDF.
Census 2024 state boundaries; Natural Earth 1:50m countries
County Map Maker
Make a county map of the whole US or any state: click counties to colour them or paste county names or FIPS codes with groups or numbers, add a legend and download PNG, SVG or PDF.
Census 2024 county boundaries (1:500,000)
ZIP Code Map Maker
Paste up to 300 ZIP codes, with group names or numbers if you like, and see their real boundaries coloured on a map, with a legend and GeoJSON or KML download.
Census 2020 ZIP Code Tabulation Areas (TIGERweb)
Pin Map Maker
Drop pins on a map by address or click, give each a label and colour, then share the map with a link or download it as KML, GeoJSON or CSV — no account needed.
OpenStreetMap tiles; Photon geocoder
CSV to Map
Open or paste a spreadsheet as CSV and see its rows as points on a map — from latitude/longitude columns or addresses — coloured by any column, and export to GeoJSON or KML.
Your CSV on OpenStreetMap tiles; Photon geocoder for addresses
KML Viewer
Open a KML file in your browser and see its placemarks, paths and polygons on a map with their names, lengths and areas, then convert it to GeoJSON, GPX or CSV.
OGC KML 2.2, read in your browser
GeoJSON Viewer
Open or drop a GeoJSON file and see every feature on a map with its properties, lengths and areas, then convert it to KML, GPX or CSV — without uploading it.
GeoJSON (RFC 7946), read in your browser
GPX Viewer
Open a GPX track from a watch, phone or bike computer and see it on a map with distance, climb, descent, time, average speed and an elevation chart.
GPX 1.1, read in your browser
Country Size Comparison
Move any country on top of another, or click anywhere on the map to drop it there, and see their true sizes compared without the Mercator map's distortion, with both areas and the ratio.
Natural Earth 1:110m countries; rigid rotation on the sphere
US Map Data
ZIP codes, cities, counties, population and national parks around a point, from Census Bureau and National Park Service data.
ZIP Codes Within a Radius
Enter an address or ZIP code and a radius and get every ZIP code within that many miles, with distance, population and income, as a list to copy or a CSV.
Census 2024 Gazetteer ZCTA points; ACS 2019–2023 5-year estimates
Cities Within a Radius
Enter an address and a radius and list every city and town within it, nearest first, with population and type — filter out small places and download as CSV.
Census 2024 Gazetteer places; ACS 2019–2023 5-year estimates
Population Within a Radius
Enter an address and up to four radii (such as 1, 3 and 5 miles) and get how many people live within each, with density, from Census tract populations.
Census 2024 Gazetteer tract points; ACS 2019–2023 5-year population
Address to County Lookup
Paste one US address or a list of up to 200 and get the county and its FIPS code for each from 2020 Census blocks, ready to download as CSV.
FCC Area API (2020 Census blocks); OpenStreetMap via Photon
County Map With Cities
Pick a state and see its county map with every city and town plotted and labelled; click a county to list the cities and towns inside it with their populations.
Census 2024 county boundaries and Gazetteer places
Interactive US County Map
Explore all 3,144 US counties on one map coloured by population, density, income or home value; hover for figures, search any county and download the map or data.
Census 2024 cartographic boundaries; ACS 2019–2023 5-year estimates
Nearest National Park
Enter your address or use your location and get all 63 US national parks ranked by distance, with driving distance and time to the three nearest.
US national parks list (NPS acreage); OSRM driving routes
Time Zones, Sun & Moon
Time zones, sunrise and sunset, day and night, and the moon's position and phase, computed from published astronomical formulas.
Sun Position Calculator
Pick a place, date and time and get the sun's elevation and compass direction, plus sunrise, sunset, solar noon and day length in local time, with a chart of the sun's path that day.
NOAA solar calculator equations (Meeus, Astronomical Algorithms)
Time Zone Finder
Type any address or use your location and get its IANA time zone, current local time, UTC offset, whether daylight saving time is in effect, and the date of the next clock change.
Time zone from Open-Meteo; rules from the IANA tz database in your browser
Sunrise Sunset Calculator
Get sunrise, sunset, dawn, dusk, solar noon and day length for every day of any month at any place, in its local time with daylight saving, and download the table.
NOAA solar calculation equations; IANA tz database
Time Difference Calculator
Compare the time in several cities at once, see how many hours ahead or behind each one is, convert a time between them and find the hours that suit everyone.
IANA tz database in your browser; Open-Meteo time zone lookup
US Time Zone Map
A map of US time zones with the current time in each, their abbreviations and UTC offsets, and which areas skip daylight saving time — hover any area for its local clock.
timezone-boundary-builder (OpenStreetMap); IANA tz database
World Time Zone Map
A live map of every time zone in the world coloured by its current UTC offset, with each zone's local time on hover and the time now at every offset.
timezone-boundary-builder (OpenStreetMap); IANA tz database
Day and Night Map
See where on Earth it is day, twilight and night right now or at any time, with the points where the sun and moon are overhead, and check the light at any place.
NOAA solar equations; Schlyter lunar method
Moon Position Map
See where the moon is overhead now and where it is above the horizon, its path over the next day, phase and distance, and its direction, moonrise and moonset from any place.
Schlyter lunar method (checked against JPL Horizons)
Moon Phase Calendar
A month calendar of the moon's phase every day, with the exact times of new moon, first quarter, full moon and last quarter in your time zone, or every phase of a year.
Schlyter lunar method (checked against USNO phase tables)
Geographic Lines
The Equator, tropics, polar circles, prime meridian and date line: where they run and which countries they cross.
Equator Map
See the Equator on a map with every country it crosses, where it enters and leaves each one and how many kilometres run over land, and how far any place is from it.
Natural Earth 1:10m countries; WGS84
Tropic of Cancer Map
See the Tropic of Cancer on a map at its exact latitude for this year, with the 19 countries and territories it crosses, the length over land in each, and your distance from it.
IAU 2006 obliquity; Natural Earth 1:10m countries
Tropic of Capricorn Map
See the Tropic of Capricorn on a map at its exact latitude for this year, with the 10 countries it crosses, the length over land in each, and your distance from it.
IAU 2006 obliquity; Natural Earth 1:10m countries
Arctic Circle Map
See the Arctic Circle on a map at its exact latitude for this year, with the 8 countries it crosses, the length over land in each, and how far north or south of it any place is.
IAU 2006 obliquity; Natural Earth 1:10m countries
Antarctic Circle Map
See the Antarctic Circle on a map at its exact latitude for this year, where it crosses the Antarctic continent and how far any place is from it.
IAU 2006 obliquity; Natural Earth 1:10m countries
Prime Meridian Map
See the Prime Meridian (0° longitude) on a map with every country it crosses from the UK to Antarctica, the stretch over land in each, and how far east or west of it any place is.
Natural Earth 1:10m countries; WGS84
International Date Line Map
See the International Date Line on a map as it bends around Pacific island nations, and check the local date and time at any place on either side of it.
Natural Earth 1:10m geographic lines; IANA tz database
Math & Study
Math and science questions worked from open textbook definitions, shown step by step.
Angle Drawer Calculator
Type an angle in degrees or radians and see it drawn in standard position, with its quadrant, reference angle, coterminal angles and sin, cos and tan.
OpenStax Precalculus 2e, §5.1 Angles
College GPA Calculator
Enter each course's letter grade and credits and get your semester GPA, and your cumulative GPA with past credits.
Credit-weighted 4.0 scale
Final Grade Calculator
Enter your current grade, the grade you want and the final's weight and get the score you need on the final exam.
Weighted-average arithmetic
Percentage Increase Calculator
Enter an old and new value and get the percentage increase or decrease, or add a percentage to any number.
Percentage change formula
Roman Numeral Converter
Convert numbers to Roman numerals and back, from 1 to 3,999, including dates for tattoos and engravings.
Standard subtractive Roman notation
Yard & Garden
Landscape material, lawn and garden quantities worked from published conversion factors and rates.
Pea Gravel Calculator
Enter the area and depth and get the pea gravel you need in cubic yards, tons and bags, using a published state conversion factor you can change.
NM EMNRD conversion factors (from BLM Handbook H-3890-1)
River Rock Calculator
Enter the bed size and depth and get the river rock you need in cubic yards, tons and bags, with the weight factor and its source shown.
NM EMNRD conversion factors (from BLM Handbook H-3890-1)
Pond Volume Calculator
Enter the pond's shape, size and average or maximum depth and get its volume in gallons, litres, cubic feet and acre-feet, using Penn State Extension's method.
Penn State Extension pond measurement method
Cubic Yards to Tons Calculator
Convert cubic yards to tons, or tons to cubic yards, for gravel, sand, base course, topsoil, fill dirt and more, using a published state conversion table.
NM EMNRD conversion factors (from BLM Handbook H-3890-1)
Grass Seed Calculator
Enter your lawn's size and grass type and get the pounds of seed to buy at University of Kentucky Extension's seeding rates, adjusted for your seed tag's pure live seed.
University of Kentucky Extension AGR-52 seeding rates
Potting Soil Calculator
Enter your pots, planters or raised beds and get the potting mix needed in dry quarts, cubic feet and litres, and how many bags to buy.
Container geometry; NIST dry quart
Pond Liner Calculator
Enter your pond's length, width and deepest point and get the liner and underlay size to buy, with edge overlap, in feet or metres.
Liner sizing formula (length + 2 × depth + 2 × overlap)
Gravel Calculator
Enter the area, depth and gravel type and get the cubic yards, tons and bags to order, with the weight factor and its source.
NM EMNRD conversion factors (from BLM Handbook H-3890-1)
Mulch Calculator
Enter the bed size and depth and get the mulch you need in cubic yards and 2 or 3 cu ft bags, with the cost.
Volume arithmetic
Energy & Electrical
Power, voltage and fuel-use arithmetic from published constants and the formulas behind them.
Propane Usage Calculator
Enter your propane appliances' Btu ratings and daily run time and get the gallons you burn per day and month, how long your tank will last and the cost.
EIA heat content: propane 91,452 Btu per gallon
DC Voltage Drop Calculator
Enter the voltage, current, run length and copper wire gauge and get the voltage drop, the percent lost, the voltage at the load and the thinnest AWG that stays within your limit.
NBS Handbook 100, Copper Wire Tables
Three Phase Power Calculator
Enter the line voltage, current and power factor and get kW, kVA and kVAR — or enter the power and get the line current — for three-phase or single-phase loads.
P = √3 × V × I × PF (Kuphaldt, Lessons In Electric Circuits)
Heating Oil Usage Calculator
Enter your burner's nozzle size and run time, or your heat load, and get the gallons of heating oil used per day and month, how long your tank will last and the cost.
EIA heat content: heating oil 138,500 Btu per gallon
Electricity Cost Calculator
Enter an appliance's watts and hours of use and get its electricity cost per day, month and year at your state's average rate.
EIA Electric Power Monthly Table 5.6.A (residential price by state)
Auto & Mechanical
Engines, fittings, fluids and machining figures from published standards and textbook formulas.
Window Tint Calculator
Enter the glass VLT and the film VLT and get the combined light transmission, compare it with your state's limit, and find the darkest film that stays legal on your glass.
Net VLT = glass × film transmission
AN Fitting Size Chart
Look up 37° flare dash sizes -2 to -32 with tube size, thread and pipe size, or measure a male thread and find which dash size it is.
SAE J514 37° flare table (Ham-Let catalog)
Engine Displacement Calculator
Enter the bore, stroke and number of cylinders and get the displacement in cubic inches, cc and litres, the bore-to-stroke ratio, or the bore needed for a target size.
Swept-volume formula (stroke × π × (bore ÷ 2)² × cylinders)
SCFM to CFM Calculator
Convert standard cubic feet per minute to actual CFM, or back, for compressed air at your pressure, temperature and altitude, with the standard conditions shown.
Combined gas law (OpenStax Chemistry 2e)
Hydraulic Cylinder Force Calculator
Enter the bore, rod and pressure and get the cylinder's push and pull force in pounds, tons and kilonewtons, or the pressure needed for a force.
Force = pressure × area (OpenStax College Physics 2e)
Chip Load Calculator
Enter spindle speed, flutes and feed rate to get chip load per tooth — or chip load to get the feed rate — with feed per rev and surface speed, in inch or metric.
Haas mill speeds and feeds formulas
Dates & Time
Countdowns, date differences, ages, hours worked and clock conversions, worked out in your browser.
How Long Until…?
Type any time, such as 3pm or 17:30, and get a live countdown of the hours, minutes and seconds until it.
Your device clock (browser time zone)
Calculate Days Between Two Dates
Pick two dates and get the number of days between them, with weekdays, weeks, and years-months-days.
Gregorian calendar arithmetic
How Many Days Until Christmas?
A live countdown to December 25, with the days until every other major US holiday this year.
5 U.S.C. 6103 federal holidays (OPM); Gregorian Easter computus
Chronological Age Calculator
Enter a date of birth and get exact age in years, months and days on any date, plus total months, weeks and days.
Gregorian calendar arithmetic
Convert Time Zones
Pick a time in one city and see the same moment in another city, with daylight saving and the date change handled.
IANA tz database in your browser; Open-Meteo time zone lookup
Military Time Converter
Convert any time between 12-hour and 24-hour military time, with how it is said aloud and a full chart.
24-hour clock notation
Hours Worked Calculator
Enter start, end and break times for each day and get total hours worked, overtime over 40 and gross pay.
Shift arithmetic; U.S. DOL FLSA overtime (Fact Sheet #23)
Money & Prices
Pay, tax, tips, loans and running costs from published rates and the formulas behind them.
Take-Home Pay Calculator
Enter your salary and state and get your 2026 take-home pay after federal tax, Social Security, Medicare and state income tax.
IRS 2026 brackets; IRS Topics 751 and 560; Tax Foundation 2026 state brackets
Hourly to Salary Calculator
Turn an hourly wage into yearly, monthly, biweekly and weekly pay for your hours, or a salary back into an hourly rate.
Pay arithmetic; OPM 2,087-hour divisor for reference
Sales Tax Calculator
Pick a state, add your city's local rate and get the sales tax and total on any price, or take the tax back out of a total.
Tax Foundation 2026 state and local sales tax rates
Tip Calculator
Enter the bill and tip percentage and get the tip, the total and each person's share, rounded up if you like.
Percentage arithmetic
Monthly Car Payment Calculator
Enter the price, down payment, trade-in, tax, APR and term and get your monthly car payment and total interest.
Standard amortizing loan formula
Gas Cost Calculator
Enter the trip distance, your car's mpg and the gas price and get the fuel cost for the trip, one way or round trip, split by riders.
Fuel arithmetic; optional OSRM road distance
Gold Price per Gram
Today's gold and silver spot price per gram, tola and ounce for 24k, 22k, 18k, 14k and sterling, in your city's currency.
gold-api.com spot price; ExchangeRate-API currency rates
Text & Writing
Count, convert and restyle text, with the rules each conversion follows shown on the page.
Word Counter
Paste or type text and get the word count, characters with and without spaces, sentences, paragraphs and reading time.
Text segmentation in your browser; Brysbaert (2019) reading rate
Case Converter
Convert text to UPPERCASE, lowercase, Title Case, Sentence case, camelCase, snake_case and more, then copy it.
Case rules stated on the page
Fancy Font Generator
Type your text and copy it in bold, italic, script, gothic, outline, monospace and circled letters for bios and posts.
Unicode Mathematical Alphanumeric Symbols
Random & Games
Random pickers, team makers and party games, with the method behind every result stated plainly.
Spin the Wheel
Type your options, spin the wheel and get a fair random pick, with the option to remove each winner.
Web Crypto random numbers
Random Team Generator
Paste a list of names and split them into random, evenly sized teams by number of teams or team size.
Web Crypto random shuffle
Random Username Generator
Generate random usernames from word pairs or your own name, with your choice of separator, numbers and length limit.
Word lists and Web Crypto random numbers
Dog Years to Human Years
Enter your dog's age and get its age in human years by the general rule and by the 2020 DNA-methylation formula.
Wang et al. 2020 (Cell Systems); general 15/9/5 rule
Love Calculator
Enter two names and play the classic paper love games, FLAMES and the LOVES letter count, with every step shown.
FLAMES and LOVES paper games (letter counting)
Zodiac Compatibility
Pick two zodiac signs or birthdays and see the aspect between them, their elements and modalities, and what astrological tradition says.
Astrological sign and aspect tables (via Wikipedia)
Suggesting a tool
A tool gets built here when the answer depends on what you enter, the data behind it is public and free to cite, and the options that already exist are genuinely poor — an official database with an unusable interface, a figure buried in a PDF, or a calculation people do by hand. If something you keep looking up fits that description, send it to [email protected].