Convert Calories to Joules
cal to J · energy conversion
What are calories and joules?
A small calorie is the energy to heat one gram of water by 1 °C, about 4.184 J. The joule is the SI unit of energy, the work done by one newton acting over one meter. For reference: a food Calorie is one kilocalorie (4,184 J), and home electricity is billed in kilowatt-hours.
How to convert calories to joules
1 cal = 4.184 J. To convert, multiply the number of calories by 4.184. For example, 5 cal = 20.92 J, and 20 cal = 83.68 J. To go the other way, multiply joules by 0.239006 (since 1 J = 0.239006 cal).
Calories to Joules conversion table
| Calories (cal) | Joules (J) |
|---|---|
| 1 | 4.184 |
| 10 | 41.84 |
| 100 | 418.4 |
| 500 | 2,092 |
| 1,000 | 4,184 |
| 2,000 | 8,368 |
| 5,000 | 20,920 |
FAQ
What is 1 cal in J?
1 cal = 4.184 J. To convert any amount, multiply the number of calories by 4.184.
How do I convert joules back to calories?
Go the other way: 1 J = 0.239006 cal, so multiply joules by 0.239006 to get calories.
Is a calorie bigger than a joule?
Yes — 1 cal is the larger unit, equal to 4.184 J.
Are these energy conversions exact?
They use the standard internationally-defined conversion factors. Results are rounded to six significant figures for readability, which is accurate enough for everyday and most technical use.