Units and calculators explained

Calculators for energy used in the United States

• Coal
• Electricity
• Natural gas
• Crude oil
• Gasoline
• Diesel fuel and heating oil
• Food calories

Note: Btu is British thermal units.

Coal conversion calculator

short tons Btu megajoules metric tons

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1 short ton=18,792,000 Btu (based on U.S. electric power sector consumption in 2026; estimate)

Electricity conversion calculator

kilowatthours Btu megajoules million calories

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1 kilowatthour=3,412 Btu (standard conversion factor)

Natural gas conversion calculator

cubic feet Btu megajoules cubic meters

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1 cubic foot=1,036 Btu (based on U.S. average for natural gas delivered to consumers in 2026; estimate)

Crude oil conversion calculator

barrels Btu megajoules liters

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1 barrel=42 U.S. gallons=5,689,000 Btu (based on U.S. production in 2026; estimate)

Gasoline conversion calculator

gallons Btu megajoules liters

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1 gallon=120,166 Btu (based on U.S. finished motor gasoline [includes fuel ethanol content] consumption at 5,047,000 Btu per barrel in 2026; estimate)

Diesel fuel and heating oil conversion calculator

gallons Btu megajoules liters

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1 gallon=137,381 Btu (for distillate fuel with 15 ppm or less sulfur content at 5,770,000 Btu per barrel in 2026; estimate)

Measuring energy in food

Food calories are a measure of energy in food. One food calorie is equal to 1,000 calories, or 1 kilocalorie. For example, the energy in a 300 food-calorie ice cream cone is about the same as the amount of electricity required to light a 100-watt incandescent light bulb for 3.5 hours.

Food energy conversion calculator

food calories Btu megajoules kilowatthours

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1 food calorie=1,000 calories, or 1 kilocalorie, or 3.9683 Btu

Scientific notation explained

Scientific notation is a shorthand way of writing a number that has a lot of digits. For example, the number 525,000,000 could be written as 5.25E+08. The +08 indicates the decimal should be moved eight places to the right. A negative number after the E means the decimal should be moved that number of places to the left. For example, 5.25E-03 is the same as 0.00525.