Converters
Energy converter
Convert joules, kilojoules, calories, kilocalories, watt-hours and kWh in an instant.
- Instant
- Free
- Private (processed locally)
- No sign-up
Convert energy in an instant
Type a value in any field — J, kJ, cal, kcal, Wh, kWh — and read all equivalents. Ideal for nutrition, electricity bills and physics exercises.
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Pick a unit
J, kcal, kWh…
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Type a value
The others compute themselves.
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Read the references
Equivalence table.
Key equivalents
- 1 cal = 4.184 J
- 1 kcal = 4,184 J = 4.184 kJ
- 1 Wh = 3,600 J
- 1 kWh = 3,600,000 J
Some references
| Energy | J | kcal |
|---|---|---|
| 1 kJ | 1,000 | 0.239 |
| 1 kcal | 4,184 | 1 |
| 1 Wh | 3,600 | 0.860 |
| 1 kWh | 3,600,000 | 860.42 |
100% local and instant conversion. No data transmitted.
Frequently asked questions
How many joules in a calorie?
1 calorie = 4.184 J. 1 kcal (food Calorie) = 4,184 J = 4.184 kJ. 1 Wh = 3,600 J. 1 kWh = 3,600,000 J.
Calorie or kilocalorie?
In nutrition, the “Calorie” (capital C) is actually a kilocalorie. On labels, kcal and kJ are often shown side by side.
How do the linked fields work?
All units share the joule as a base. Type a value in one field and the others update instantly.
Is my data uploaded?
No. The conversion is instant and purely local, with no network calls.