Kilojoules to Calories (kJ to cal) Converter
1 kilojoule equals 239.005736 calories — multiply the number of kilojoules by 239.005736 to convert to calories. Note these are small (thermochemical) calories, not the "food Calories" (kilocalories) on nutrition labels.
The formula
To convert kilojoules to calories, multiply by 239.005736:
calories = kilojoules × 239.005736
For example, 4 kJ × 239.005736 = 956.0229 cal. The reverse factor is 1 cal = 0.004184 kJ.
Conversion table
| Kilojoules (kJ) | Calories (cal) |
|---|---|
| 1 | 239.005736 |
| 2 | 478.011472 |
| 5 | 1195.028680 |
| 10 | 2390.057360 |
| 25 | 5975.143400 |
| 50 | 11950.286800 |
| 100 | 23900.573600 |
| 500 | 119502.868000 |
| 1000 | 239005.736000 |
How to convert online
- Type the number of kilojoules into the first box.
- Read the equivalent calories instantly in the second box.
- Or enter a calorie value to convert back to kilojoules — it works both ways.
Use the Kilojoule to Calorie Converter — free and instant in your browser.
Where this conversion is used
Energy in kilojoules and calories appears in physics and chemistry problems, thermodynamics, engineering heat calculations and food science. Many countries label food energy in kilojoules while calorie counters and older references use calories, so this conversion bridges the two systems whenever you compare or report energy values.
FAQ
How many calories are in a kilojoule?
239.005736 small calories. So 10 kJ = 2390.057360 cal.
What is the formula to convert kilojoules to calories?
cal = kJ × 239.005736. The converter applies the exact factor automatically.
How do I convert calories back to kilojoules?
Divide by 239.005736, or multiply by 0.004184. For example, 500 cal ≈ 2.092 kJ.
Are these food Calories?
No. These are small calories. One food Calorie equals 1000 small calories (a kilocalorie); use the kJ to kcal converter for nutrition labels.
Related converters
- Calorie to Kilojoule Converter
- Kilojoule to Kilocalorie Converter
- Kilojoule to Joule Converter
- Kilojoule to Watt-hour Converter
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