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.
Stamped on the burner nozzle, e.g. 0.75, 0.85, 1.00.
The usable gallons you have now, not the tank's size.
The result updates as you type.
heating oil use
5.1 gallons per day
153 gallons per 30 days · 49 days from 250 gallons
| Fuel burned per day | 706,350 Btu |
| Heat content of heating oil | 138,500 Btu per gallon (EIA) |
What this page cannot tell you
How long your appliances actually run. Run time swings with the weather, thermostat settings and household use; a heating appliance can run several times longer on a cold day than a mild one. Tank gauges read in percent of the tank's size, and not all of that is usable.
How to calculate heating oil usage
- Find the nozzle size. The firing rate in gallons per hour (GPH) is stamped on the burner nozzle or listed on the service tag.
- Estimate burner run time. Hours per day the burner actually fires.
- Or use Btu ratings or heat load. Switch modes if you know appliance Btu/h or a daily heat need.
- Enter the oil on hand. Gallons in the tank now, for days remaining.
- Add the price. Optional, for cost per day and month.
10 situations where a heating oil usage calculator helps
Timing a delivery
Days remaining from the gallons in the tank and your daily use.
Budgeting a winter
Monthly gallons × price.
After a burner service
A smaller nozzle changes gallons per burner hour.
Comparing boilers
Btu input ratings turned into gallons.
Checking delivery bills
Compare gallons delivered with expected use.
Cold snaps
See how longer run times shorten tank life.
Choosing a tank size
How often a 275 or 330 gallon tank would need filling at your use.
Switching fuels
Btu figures for comparison with propane or electric.
Rental properties
Estimate oil costs for a tenant's heating.
Water heating from the boiler
Add the hours the burner fires for hot water.
Where the numbers come from
An oil burner's nozzle is rated in gallons per hour, so oil burned = nozzle GPH × burner hours. When you start from appliance ratings, gallons = Btu per hour × hours ÷ 138,500, the U.S. Energy Information Administration's heat content for heating oil (1 gallon = 138,500 Btu). From a delivered heat load, the page divides by the appliance's efficiency first.
Days remaining = gallons in the tank ÷ gallons per day; monthly figures use 30 days.
Limits: burner run time is the big unknown and swings with outdoor temperature; one daily figure is an average. Tank gauges show fractions of the tank, and the bottom of a tank isn't all usable. Everything runs in your browser.
Sources
- U.S. Energy Information Administration — British thermal units (Btu) — 1 gallon of heating oil = 138,500 Btu
Frequently asked questions
How much oil does my furnace use per hour?
About the nozzle's rating: a 0.85 GPH nozzle burns 0.85 gallons for every hour the burner runs.
How long will 200 gallons of heating oil last?
200 ÷ your gallons per day. At 5 gallons a day, 40 days.
How many Btu are in a gallon of heating oil?
138,500 according to the EIA.
How do I find burner run time?
Some controls log it; otherwise time the burner over a day, or estimate from past deliveries and dates.
Why does usage vary so much?
Heating demand depends on outdoor temperature, so run time changes day to day.
Does this include hot water?
If the boiler heats your water, include those burner hours too.
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