Home Fuel Math

Practical calculators for homes heated with oil, propane, pellets or wood. How many gallons are in the tank? When will it run out? How long will a 20 lb tank run the heater? What's the cheapest way to heat this winter? Each tool shows its formula and cites where its numbers come from.

• Oil Tank Chart Calculator

  Stick reading or gauge to gallons for 275, 330, 500, 550 and 1000 gallon tanks, with printable charts.

• Heating Oil Days Left

  How long the oil in your tank will last, and the date you should order by.

• Heating Oil Usage Calculator

  Gallons per day, month and season from your delivery slips, and whether that is normal.

• Propane Tank Calculator

  Gauge percent or cylinder weight to gallons, the 80% fill rule, and days left.

• Propane Runtime Calculator

  How long a 1 lb, 20 lb or 100 lb tank runs a Buddy heater, Blackstone, grill, patio heater or RV furnace.

• Propane Generator Runtime

  Hours and days a tank will run a Generac or Kohler standby generator at your load.

• Wood Pellet Calculator

  Bags per day and per season, tons to order, and what a winter of pellets costs.

• Firewood Cord Calculator

  Cords, face cords and ricks from a stack size, and how much firewood you need for winter.

• Heating Fuel Cost Comparison

  Oil, propane, gas, electric, heat pump, pellets, wood and kerosene in dollars per million Btu delivered.

• Heat Pump vs Oil Calculator

  Yearly cost of a heat pump against your oil boiler or furnace, break-even electric rate and payback.

Built for real questions, not guesswork

Tank charts here are for the standard tank sizes you'll actually find in a basement or buried in a yard, and the 275 and 330 gallon charts follow Granby Industries' published chart. Appliance and generator presets use the Btu ratings and fuel tables published by Mr. Heater, Blackstone, Weber, Generac, Kohler and other manufacturers. Energy content and average-home comparisons come from the U.S. Energy Information Administration. Everything runs in your browser, with no sign-up, and nothing you type is sent anywhere.

A few things to keep in mind

These are estimates. Your tank, appliance and house can differ from the published figures, and fuel prices change weekly. Use the results to plan, then confirm with your fuel supplier or a licensed heating professional before you make a decision that matters. Never run outdoor propane appliances indoors, and keep a working carbon monoxide alarm on every floor.