How to convert joules to calories
- Take the value in joules.
- Use the formula calories = joules ÷ 4.184.
- For example, 1 J is 0.239 cal.
About joules and calories
This page uses the small calorie (thermochemical calorie), defined as exactly 4.184 joules. Divide joules by 4.184 to get calories, or multiply by 0.24 for an estimate that is about 0.4% high.
The small calorie is roughly the heat needed to warm 1 gram of water by 1 °C, which is why it still turns up in chemistry and physics problems. Food labels use the kilocalorie, 1,000 of these, so for food energy use the kilojoules to kilocalories page.
Examples
- 1 J (lifting a small apple (about 100 g) by 1 m) is 0.239 cal
- 4.18 J (warming 1 g of water by 1 °C) is 1 cal
- 3,600 J (one watt-hour) is 860.42 cal
- 4,184 J (one food Calorie (kcal)) is 1,000 cal
Joules to calories chart
| Joules (J) | Calories |
|---|---|
| 1 | 0.239 |
| 2 | 0.478 |
| 4.18 | 1 |
| 5 | 1.2 |
| 10 | 2.39 |
| 20 | 4.78 |
| 50 | 11.95 |
| 100 | 23.9 |
| 250 | 59.75 |
| Joules (J) | Calories |
|---|---|
| 500 | 119.5 |
| 1,000 | 239.01 |
| 2,000 | 478.01 |
| 3,600 | 860.42 |
| 4,184 | 1,000 |
| 5,000 | 1,195.03 |
| 10,000 | 2,390.06 |
| 100,000 | 23,900.57 |
| 1,000,000 | 239,005.74 |