Joules (J) to Calories (cal) Conversion
Joules
The joule (J) is the SI derived unit of energy, work, and heat, defined as the work done when a force of one newton displaces an object by one metre (J = N·m = kg·m²·s⁻²). Named after James Prescott Joule, who established the mechanical equivalent of heat in the 1840s, the joule unifies all forms of energy — mechanical, thermal, electrical, chemical, and nuclear — under one framework. One joule is small: lifting an apple (≈100 g) one metre requires about 1 joule, while a human at rest metabolises approximately 80 joules per second.
Calories
The calorie (cal) is a unit of energy equal to exactly 4.184 joules, defined as the energy required to raise the temperature of one gram of water by one degree Celsius at 15 °C. This is the thermochemical calorie — distinct from the food calorie (written as Cal or kcal), which is 1,000 times larger. The calorie originated in 19th-century thermodynamics before the joule was established as the SI standard, and persists in chemistry, biology, and food science.
| Joules (J) | Calories (cal) |
|---|---|
| 0.1 J | 0.023900573613767 cal |
| 1 J | 0.23900573613767 cal |
| 2 J | 0.47801147227533 cal |
| 3 J | 0.717017208413 cal |
| 5 J | 1.1950286806883 cal |
| 10 J | 2.3900573613767 cal |
| 20 J | 4.7801147227533 cal |
| 30 J | 7.17017208413 cal |
| 50 J | 11.950286806883 cal |
| 100 J | 23.900573613767 cal |
| 1000 J | 239.00573613767 cal |
Frequently Asked Questions (FAQ)
How many calories are in 1 joules?
1 joules (J) is exactly 0.239006 calories (cal).
How do I convert joules to calories?
Multiply the value in joules by 0.239006 to get the result in calories. Or use the converter above — type any number and see the result instantly.