Heating oil calculators

Pick a calculator

• Heating oil tank calculator (level to gallons)

  Turn tank dimensions and a stick reading into gallons, for tanks that do not match a standard chart.

• Heating oil usage calculator

  Get gallons per day from two delivery slips, or estimate a heating season from home size and insulation.

• How long will my oil last

  Divide the gallons in your tank by a daily burn rate to get days remaining and the date to order by.

• Buried tank size identifier

  Identify a buried tank from one delivery: stick before, note the ticket gallons, stick after.

• What size tank do I need?

  Buying or replacing a tank? NORA's sizing rule turns your annual gallons into the right tank size.

• Burner fuel use and nozzle chart

  Nozzle rated GPH plus pump pressure plus hours run equals gallons burned, with the full nozzle flow chart.

• Nozzle converter (for techs)

  For techs: stamped GPH to actual at any PSI, the reverse lookup for substitutions, and a printable chart.

Have a standard tank? Use a chart

If your tank is one of the common sizes (275, 330, 550, or 1000 gallons), you do not need a calculator at all. The tank charts convert any stick or gauge reading straight to gallons, and they print cleanly for the boiler room wall. Not sure which size you have? Start with what size is my oil tank.

Run them in the right order

• Inches first, then days left. The days-left page takes gallons, not inches. Convert a stick reading at your tank's chart, or at the tank calculator if the tank is an odd one, before you land there.
• Usage, then days left. Days left opens on a typical-winter preset of about 5 gallons a day, which stands in until you have measured your own. Two delivery slips through the usage calculator give a real gallons-per-day figure, and the custom rate box on the days-left page accepts it directly.
• Watch what you carry into tank sizing. The usage calculator projects a year from whatever span you measured, and it warns that a winter span reads high. Its worked example, 220 gallons over 40 days, is 5.5 gallons a day, which projects to just over 2,000 gallons a year. Hand that to tank sizing, whose rule divides annual gallons by three, and it comes back with a multi-tank setup. Size from a full year, not from a winter span.

What these tools cannot do

• None of them read your tank. Every answer starts from a number you supply, whether that is a measurement, a delivery ticket, a date, or a meter reading.
• None of them watch the weather. Days left divides at whatever rate you picked and never revises it, so a turn in the weather means going back and picking again.
• The tank calculator works from the dimensions you type and treats the ends as flat, so on a standard steel oval it comes in under the charted capacity. Enter a 275 vertical at 27 by 44 by 60 inches and it returns 268 gallons full, while the 275 vertical chart reads 274 at 44 inches. The gap is the 2.2 percent dished-head allowance the charts carry and a bare dimension cannot know about. On a standard tank, trust the chart.
• Nothing here turns gallons into money or places an order.