Energy Converter
Convert between joules, kilojoules, calories, kilocalories, watt-hours, kilowatt-hours and BTU. One kilowatt-hour equals 3.6 million joules.
Energy Converter
The "Calorie" on a food label is a kilocalorie (kcal): 1 kcal = 4.184 kJ.
Food Energy Reference
kJ ↔ kcal (EU/AU use kJ, US uses kcal)
| Food | kcal | kJ |
|---|---|---|
| Apple (medium) | 95 | 397 |
| Slice of bread | 79 | 330 |
| Banana | 105 | 439 |
| Boiled egg | 78 | 326 |
| Can of cola (330ml) | 139 | 581 |
| Chocolate bar (50g) | 250 | 1046 |
| Daily adult intake (avg) | 2000 | 8368 |
💡 Food labels say "Calorie" but mean kilocalorie (kcal). 1 food Calorie = 1 kcal = 4.184 kJ.
Convert energy between kilojoules, calories, kilowatt-hours, and BTU — for nutrition, electricity bills, and engineering.
Formula
1 kcal = 4.184 kJ. 1 kWh = 3,600 kJ. 1 BTU = 1.055 kJ.
Reference Values
- •1 kcal (food calorie) = 4.184 kJ
- •1 kWh = 3,600 kJ
- •1 BTU = 1.055 kJ
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FAQ
Common questions about energy conversion
How we calculate this
We use the standard published formula for this calculation, and we show the working so you can check it.
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