Kilocalories to Kilojoules (kcal to kJ) Converter
1 kilocalorie equals 4.184 kilojoules — multiply kilocalories by 4.184 to convert kcal to kJ. This is the conversion behind the dual "kcal / kJ" figures printed on food labels worldwide.
The formula
To convert kilocalories to kilojoules, multiply by the exact factor:
kJ = kcal × 4.184
For example, 250 kcal × 4.184 = 1,046 kJ. The factor is the same 4.184 that relates calories to joules, just scaled up by the kilo prefix on both sides.
Conversion table
| Kilocalories (kcal) | Kilojoules (kJ) |
|---|---|
| 1 | 4.184 |
| 2 | 8.368 |
| 5 | 20.92 |
| 10 | 41.84 |
| 25 | 104.6 |
| 50 | 209.2 |
| 100 | 418.4 |
| 500 | 2,092 |
| 1000 | 4,184 |
How to convert online
- Type the number of kilocalories into the first box.
- Read the kilojoule result instantly in the second box.
- Or enter a kJ value to convert back to kilocalories — it works both ways.
Use the Kilocalorie to Kilojoule Converter — free and instant in your browser.
Where this conversion is used
Food labels in the EU, UK, Australia and many other regions list energy in kilojoules, while calorie counters and US labels use kilocalories. Converting kcal to kJ lets you compare products across regions, log meals in whichever unit your app expects, and understand a nutrition panel that shows both numbers side by side.
FAQ
How many kilojoules are in a kilocalorie?
One kilocalorie equals 4.184 kilojoules.
Is 100 kcal the same as 418.4 kJ?
Yes. 100 kcal × 4.184 = 418.4 kJ, which is why both figures often appear together on labels.
How do I convert kilojoules back to kilocalories?
Divide the kilojoule value by 4.184 (or multiply by 0.23900574). For example, 2,092 kJ = 500 kcal.
Is the conversion exact?
Yes. The thermochemical kilocalorie is defined as exactly 4.184 kilojoules.
Related converters
- Kilojoule to Kilocalorie Converter
- Kilocalorie to Joule Converter
- Kilocalorie to Calorie Converter
- Kilocalorie to Kilowatt-hour Converter
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