How Long Will My Heating Oil Last?
A calculator for how long your heating oil will last: enter your tank size and gauge reading to see roughly how many usable gallons and days of oil you have left, the date to reorder by (at a quarter tank — never wait for empty), and what a fill-up would cost. Estimates are deliberately conservative. Everything runs in your browser; your entries are saved locally so you can re-check all winter.
Your tank
Your burn rate
Oil price (optional, for fill-up cost)
Result
These are rough, deliberately conservative estimates — treat them that way. Float gauges stick and misread, burner efficiency drifts, and a cold snap can roughly double your daily burn overnight. Never plan to run the tank low: running dry usually means a no-heat emergency and a paid service call to bleed the fuel line and restart the burner. When in doubt, order early.
FAQ
Why reorder at a quarter tank instead of near empty?
Three reasons: dealers get backed up exactly when everyone else is low (a cold-snap delivery can take days), a cold snap can double your burn rate at the same time, and gauges commonly read higher than the true level. A quarter tank on a typical 275 is about 60 usable gallons — roughly one to two weeks of typical winter burn — which is the buffer that keeps a late truck from becoming a no-heat emergency. That's why this tool computes its "order by" date at the quarter-tank point, using the fast end of your burn range.
Why does a “275 gallon” tank only hold about 240 gallons?
Tanks are never filled to the nameplate number: deliveries stop short to leave room for air and expansion, and the outlet line sits above the very bottom where water and sludge collect. Dealers typically fill a 275 to roughly 240–250 gallons, and not all of that is usable. This tool assumes about 87% of nameplate capacity is usable oil, which is on the conservative side on purpose.
How accurate is the estimated burn rate?
It's a rule of thumb, calibrated to figures heating-oil dealers publish: a typical home burns around 2 gallons a day at 50°F outside, about 5 at 30°F, and 7–8 when it stays below 20°F. Your insulation, thermostat setting, windows, and burner condition can easily move that 30% either way — which is why the result is a range, never a single number. If you know your real gallons-per-day from delivery records, use the direct entry; it will always beat the estimate.
Does the oil last longer in summer?
Much longer. If your heat is off and your hot water is electric or gas, you burn essentially nothing. If your hot water runs on oil, expect a baseline of roughly 0.5–1.5 gallons a day year-round — the hot-water toggle above adds about 1 gal/day to the estimate.
Where do I get the price per gallon?
Prices vary a lot by region, dealer, and week — check two or three local quotes or your state's energy office survey before ordering. We currently have no affiliate relationships with any dealer or ordering platform; nothing here earns us money from your order.