Energy Converter
Convert energy between joules, kilojoules, calories, kilocalories, watt-hours, kilowatt-hours, and British thermal units, for example for food labels, electricity bills, or heating specifications.
Formula: multiply the source value by 3,600
Quick Conversions
About this tool
Energy is converted through the joule. A thermochemical calorie is 4.184 J. A kilowatt-hour is 3.6 million joules.
How to use it
Enter an energy value, choose the source and target units, and read the live result.
value_to = value_from × (from_in_joules / to_in_joules)
Examples
1 kWh to kJ
1 × 3,600,000 / 1,000 = 3,600 kJ.
2,000 kcal to kJ
2,000 × 4.184 = 8,368 kJ.
1 kWh to BTU
1 × 3,412.14 = 3,412.14 BTU.
Every unit expressed in joules
| Unit | Equal to (J) |
|---|---|
| 1 joule (J) | 1 |
| 1 kilojoule (kJ) | 1,000 |
| 1 calorie (cal) | 4.184 |
| 1 kilocalorie (kcal) | 4,184 |
| 1 watt-hour (Wh) | 3,600 |
| 1 kilowatt-hour (kWh) | 3,600,000 |
| 1 British thermal unit (BTU) | 1,055.055853 |
FAQ
Is a calorie the same as a food Calorie?
Food labels use kilocalories (kcal). 1 kcal = 1,000 cal = 4,184 J.
What BTU is used here?
The International Table BTU, about 1,055.06 J.
Which calorie and BTU are used?
The thermochemical calorie (exactly 4.184 J) and the International Table BTU (about 1,055.06 J). A food Calorie with a capital C is a kilocalorie.