Convert joules to calories
Converting joules to calories is a common energy task, whether you are checking a recipe, a spec sheet, a travel distance or a homework problem. Since 1 J equals 0.239006 cal, the math is a single multiplication — and this page does it for you instantly, with the formula, a table of common values and answers to the questions people ask most.
Exact factor
How to convert joules to calories
To convert joules to calories, multiply the number of joules by 0.239006. For example, 10 J × 0.239006 = 2.39006 cal.
cal = J × 0.239006
- Write down the value in joules you want to convert.
- Multiply it by 0.239006 (the exact J→cal factor).
- The result is your value in calories. Check it below with the converter or the table.
Conversion table
Common values of joules and their equivalents in calories:
| J | cal |
|---|---|
| 1 | 0.239006 |
| 2 | 0.478011 |
| 3 | 0.717017 |
| 4 | 0.956023 |
| 5 | 1.19503 |
| 10 | 2.39006 |
| 20 | 4.78011 |
| 25 | 5.97514 |
| 50 | 11.9503 |
| 100 | 23.9006 |
| 250 | 59.7514 |
| 500 | 119.503 |
About these units
Joule (J). The joule is the SI unit of energy: the work done by one newton acting over one meter. Food labels in most countries, physics and engineering use joules.
Calorie (cal). The small calorie is the energy needed to raise one gram of water by 1 °C, defined as exactly 4.184 joules. It is mostly used in chemistry and heat calculations.
Frequently asked questions
How do I convert joules to calories?
To convert joules to calories, multiply the number of joules by 0.239006. For example, 10 J × 0.239006 = 2.39006 cal. Or skip the math: type the value into the converter at the top of this page and the result updates instantly.
How many calories are in 1 joule?
1 J = 0.239006 cal. That is the fixed relationship used by this converter and by international standards.
How many joules are in 1 calorie?
1 cal = 4.184 J. If you are converting in the opposite direction, use our Calorie to Joule converter for the dedicated table and FAQ.
Is the joules to calories conversion exact?
Yes. Both units are defined by international agreement, so the factor of 0.239006 is exact. Displayed results are rounded to 6 significant digits only for readability.
What is joule used for?
The joule is the SI unit of energy: the work done by one newton acting over one meter. Food labels in most countries, physics and engineering use joules.