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.
Push a clean stick straight down to the bottom at the fill pipe and read the wet line in inches. The chart updates as you type.
12.0″ of oil in a 275 gal tank, 44″ tall
≈ 66 gallons
23.8% full · room for about 209 more gallons to the rated capacity.
Inch-by-inch chart for this tank
| Inches of oil | Gallons | % full |
|---|---|---|
| 1″ | 2 | 1% |
| 2″ | 5 | 2% |
| 3″ | 9 | 3% |
| 4″ | 14 | 5% |
| 5″ | 19 | 7% |
| 6″ | 25 | 9% |
| 7″ | 31 | 11% |
| 8″ | 38 | 14% |
| 9″ | 45 | 16% |
| 10″ | 51 | 19% |
| 11″ | 58 | 21% |
| 12″ | 66 | 24% |
| 13″ | 73 | 26% |
| 14″ | 80 | 29% |
| 15″ | 87 | 32% |
| 16″ | 94 | 34% |
| 17″ | 102 | 37% |
| 18″ | 109 | 40% |
| 19″ | 116 | 42% |
| 20″ | 123 | 45% |
| 21″ | 130 | 47% |
| 22″ | 138 | 50% |
| 23″ | 145 | 53% |
| 24″ | 152 | 55% |
| 25″ | 159 | 58% |
| 26″ | 166 | 60% |
| 27″ | 173 | 63% |
| 28″ | 181 | 66% |
| 29″ | 188 | 68% |
| 30″ | 195 | 71% |
| 31″ | 202 | 74% |
| 32″ | 209 | 76% |
| 33″ | 217 | 79% |
| 34″ | 224 | 81% |
| 35″ | 230 | 84% |
| 36″ | 237 | 86% |
| 37″ | 244 | 89% |
| 38″ | 250 | 91% |
| 39″ | 256 | 93% |
| 40″ | 261 | 95% |
| 41″ | 266 | 97% |
| 42″ | 270 | 98% |
| 43″ | 273 | 99% |
| 44″ | 275 | 100% |
What this page cannot tell you
Exactly what is in your tank. The figures assume the tank’s nominal dimensions, a level tank and a stick reading taken at the centre. Real tanks differ slightly by maker, sit at a slight tilt, and keep some oil and sludge below the outlet that the burner cannot use. Treat the result as an estimate.
How to read your oil tank in gallons
- Pick your tank. A standard 275 or 330 gallon oval tank, standing on end (vertical) or lying flat (horizontal), a round 500, 550 or 1000 gallon tank, or enter your own dimensions.
- Stick the tank. Lower a clean wooden stick through the fill pipe to the bottom and read the wet line in inches.
- Enter the inches. The gallons, percent full and room left appear at once.
- Keep the chart. The full inch-by-inch chart for your tank is listed under the result.
10 situations where an oil tank chart helps
Ordering a delivery without overfilling
Know how much room is left before the truck arrives, so you order a fill the tank can actually take.
Checking a gauge you don't trust
Float gauges stick. A stick reading and the chart give an independent number.
Avoiding a run-out in a cold snap
Turn inches into gallons and compare with how much you burn per week.
Buying a house with an oil tank
Sellers are often credited for the oil left in the tank; know the gallons, not just 'about a third'.
Checking a delivery ticket
Stick before and after a fill and compare the change with the gallons billed.
Understanding why a vertical tank reads oddly
In an oval tank on end, the first and last inches hold far less oil than the middle ones.
Planning a tank removal
Estimate how much oil has to be pumped out before a tank is taken away.
Comparing a new tank's size
See how much more a 330 holds at the same depth than a 275.
Tracking oil use over a season
Weekly stick readings turned into gallons give a burn rate.
Non-standard tanks
Enter the dimensions of a round, oval or box tank and get a chart for it.
How the gallons are worked out
There is no single official chart: oil dealers publish their own, built the same way. A tank is treated as a cross-section — an oval (two half-circles joined by straight sides), a circle, or a rectangle — run along its length. The share of the tank that is full is the area of the cross-section below the oil line divided by the whole cross-section, using the standard circular-segment area formula for the rounded parts. That share is multiplied by the tank's rated capacity.
Checked on 2026-10-14 against pickhvac.com's published 275-gallon charts: this method reproduces every row of the vertical chart (44 rows) to within 1.6 gallons, and every row of the horizontal chart (27 rows) to within 2.8 gallons — that chart's own steps are uneven. The geometric volume of the nominal outside dimensions is shown too: a 27" × 44" × 60" oval holds about 268 gallons by geometry against its 275 rating, and a 48" × 72" cylinder about 564 gallons against 550.
The preset dimensions are the standard sizes listed by pickhvac.com — 275 and 330 gallon oval tanks 27" by 44" and 60" or 72" long, and 48"-diameter cylinders 65", 72" and 130" long for 500, 550 and 1000 gallons — which match Granby's 27" wide by 44" tall 330-gallon vertical tank. A tank from another maker may differ by a fraction of an inch.
Limits: the result assumes a level tank, a reading at the centre, and nominal dimensions. Not all of the oil is usable — some sits below the outlet with sludge and water. Nothing here replaces a tank inspection or a dealer's reading for a sale or a dispute.
Sources
- pickhvac.com — Oil Tank Standard Sizes — Preset dimensions
- pickhvac.com — 275 Gallon Oil Tank Chart — Independent chart used to check the method
- Ferguson — Granby 330 gal vertical oil tank — 27" width, 44" height
Frequently asked questions
How many gallons are in a 275 gallon oil tank at 10 inches?
About 51 gallons if the tank stands on end (vertical, 44" tall), and about 97 gallons if it lies flat (horizontal, 27" tall).
How do I know if my 275 tank is vertical or horizontal?
Vertical tanks stand on their narrow end with the rounded edges at top and bottom and are about 44" tall. Horizontal tanks lie flat and are about 27" tall.
Why don't the first few inches hold much oil?
In a vertical oval tank the bottom is rounded, so the lowest inches are narrow. The middle inches, where the sides are straight, each hold the same amount.
How do I read the gauge on top of my oil tank?
A float gauge shows roughly how full the tank is (F, ¾, ½, ¼). It is easily stuck; a stick reading converted with the chart is a useful check.
Is a 275 gallon tank really 275 gallons?
Its rating is 275. The oil you can actually use is less, because you never fill to the very top and some oil stays below the outlet.
How do I stick an oil tank safely?
Use a clean wooden stick through the fill pipe, keep flames and sparks away, and wipe it before taking it out.
My tank isn't listed. Can I still use this?
Yes. Choose 'Other' and enter its shape, height, width, length and, if you know it, its rated capacity.
Related tools
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)