Convert Kilojoules to Calories
1 kilojoule is 239.005736 cal. One kilojoule is exactly 239.005736138 calories.
One kilojoule is 239.00574 calories. To convert kilojoules to calories, multiply by 239.00574; to go the other way, divide by 239.00574 or multiply by 0.004184. The factor is exact rather than rounded: it follows from NIST Special Publication 811. A thousand joules.
Factor checked against the defining standard · How we check
- Kilojoules × 239.00574
value * 239.005736138239.006 cal
1 kilojoule in every energy unit
| Unit | Value | Exact factor |
|---|---|---|
| joules | 1,000 J | × 1,000 |
| kilojoules (as entered) | 1 kJ | — |
| calories | 239.0057361 cal | × 239.005736138 |
| kilocalories | 0.2390057361 kcal | × 0.239005736138 |
| watt-hours | 0.2777777778 Wh | × 0.277777777778 |
| kilowatt-hours | 0.0002777777778 kWh | × 0.000277777777778 |
| British thermal units | 0.9478171203 BTU | × 0.947817120313 |
| foot-pounds | 737.5621493 ft·lbf | × 737.562149277 |
Factors are entered by hand from NIST Special Publication 811 rather than derived from a units library, so the ones that terminate are exact rather than rounded.
How do you convert kilojoules to calories?
- 1.Take the measurement in kilojoules.
- 2.Multiply by 239.00574 — that is how many calories fit in one kilojoule.
- 3.To go back the other way, divide by 239.00574, or multiply by 0.004184.
Worked example: 25 kilojoules to calories
- Formula
- kJ × 239.00574 = cal
- Arithmetic
- 25 × 239.00574 = 5,975.143403 cal
- Answer
- 25 kJ = 5,975.143403 cal
The factor is rounded for display; the figure above is computed from the full value.
Kilojoules to calories conversion table
| Kilojoules | Calories |
|---|---|
| 1 kJ | 239.005736 cal |
| 2 kJ | 478.011472 cal |
| 3 kJ | 717.017208 cal |
| 4 kJ | 956.022945 cal |
| 5 kJ | 1,195.028681 cal |
| 6 kJ | 1,434.034417 cal |
| 7 kJ | 1,673.040153 cal |
| 8 kJ | 1,912.045889 cal |
| 9 kJ | 2,151.051625 cal |
| 10 kJ | 2,390.057361 cal |
| 12 kJ | 2,868.068834 cal |
| 15 kJ | 3,585.086042 cal |
| 20 kJ | 4,780.114723 cal |
| 25 kJ | 5,975.143403 cal |
| 50 kJ | 11,950.286807 cal |
| 100 kJ | 23,900.573614 cal |
| 200 kJ | 47,801.147228 cal |
| 300 kJ | 71,701.720841 cal |
| 500 kJ | 119,502.868069 cal |
| 1000 kJ | 239,005.736138 cal |
| 2000 kJ | 478,011.472276 cal |
| 5000 kJ | 1,195,028.68069 cal |
| 10000 kJ | 2,390,057.36138 cal |
What is a kilojoule?
A thousand joules. Food energy outside the US is labelled here, alongside or instead of calories.
What is a calorie?
The thermochemical calorie: exactly 4.184 joules by definition. This is the small calorie — the one on a food label is a thousand of these, which is the single most common confusion in this group.
How many calories are in a kilojoule?
One kilojoule is 239.00574 calories. Going the other way, one calorie is 0.004184 kilojoules. Both figures come from the same defined relation rather than from a measurement, which is why they are the same today as they were in 1959.
Every energy unit here
| Unit | Symbol | One of these is |
|---|---|---|
| Joules | J | the base unit |
| Kilojoules | kJ | 1000 joule |
| Calories | cal | 4.184 joule |
| Kilocalories | kcal | 4184 joule |
| Watt-hours | Wh | 3600 joule |
| Kilowatt-hours | kWh | 3600000 joule |
| British thermal units | BTU | 1055.0559 joule |
| Foot-pounds | ft·lbf | 1.3558179 joule |
Source: NIST Special Publication 811 — the thermochemical calorie is exactly 4.184 J
Questions people actually ask
- How many calories are in a kilojoule?
- 239.00574. The thermochemical calorie: exactly 4.184 joules by definition. This is the small calorie — the one on a food label is a thousand of these, which is the single most common confusion in this group.
- How do I convert calories back to kilojoules?
- Divide by 239.00574, or multiply by 0.004184 — they are the same operation.
Other energy conversions
Calories to kilojoules — the same conversion the other way.