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Energy Converter
Convert energy between joules, kilowatt-hours, calories, BTU, electron volts, and foot-pounds. Energy unit converter.
1 joule
0.001 kilojoule
1 joule × 1 ÷ 1000 = 0.001 kilojoule
kJ0.001
kcal0.000239
kWh0
BTU0.000948
How to Use the Energy Converter
Enter your values above for an instant result. This tool uses verified formulas and is optimised for users in USA, Canada, UK, Australia. All calculations happen in your browser — your data is never sent to our servers.
Frequently Asked Questions
How do you convert calories to joules?
1 calorie (food calorie/kcal) = 4,184 joules. 100 calories = 418,400 joules or 0.116 watt-hours.