Heating Oil Tank Calculator
Pick your tank size, read the gauge, set your cold-week burn rate and the local price per gallon. The calculator gives usable gallons, days of heat left, the refill-to-full cost, and the gauge where you should order.
Two gauge truths carry this page: the tank never holds its rated number - a 275 gallon basement tank delivers about 240 usable gallons - and the float gauge is a hint, not an instrument. Order at one third, because winter queues, emergency surcharges and a bleed-the-line restart are all more expensive than planning.
How to use
- Tank size from the label; 275 is the standard basement unit.
- Read the gauge and be honest about your cold-week burn rate.
- Order at a third of a tank - the calculator shows why.
Frequently asked questions
How long will 100 gallons of heating oil last?
At a typical winter burn of 5 gallons a day, about 20 days. The real rate varies with house size and cold snaps - tracking one cold week gives you a personal number better than any rule of thumb.
Why does my 275 gallon tank only take 240 gallons?
The pickup line and the internal geometry reserve the bottom of the tank - roughly 90 percent of rated capacity is usable. The calculator applies the same factor to any size.
When should I order heating oil?
At about one third of a tank. Winter delivery queues stretch to days, emergency or will-call fills carry surcharges, and running dry means a technician visit to bleed the line before the burner restarts.
Is heating oil cheaper in summer?
Usually - summer and early-fall prices run lower and deliveries are slower-paced, so filling before the first cold snap beats panic-buying in January. The calculator prices the refill so you can time it.