Energy Converter
Convert between energy units — joules, calories, BTU, kilowatt-hours, foot-pounds, and electron-volts.
Enter a value
1 kWh =
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J
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kJ
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cal
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kcal
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BTU
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Wh
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kWh
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ft·lb
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About this converter
Food calorie vs. small calorie
The "Calorie" on food labels (capital C) is actually a kilocalorie — 1,000 small calories. This calculator labels them as kcal to avoid confusion.
Electrical energy
1 kWh = 3,600,000 J = 3,600 kJ. Used on electricity bills. A 100-watt light bulb running for 10 hours consumes 1 kWh.
BTU and HVAC
Air conditioner and furnace capacity is usually rated in BTU/hr. 1 BTU = 1,055.06 J. Common AC sizes: 5,000-15,000 BTU/hr for window units; central AC is rated in tons (1 ton = 12,000 BTU/hr).