Calories to Joules
A small calorie is the energy to raise 1 gram of water by 1°C, a base unit distinct from the food Calorie (kcal). The joule is the SI unit of energy, defined as the work done by one newton over one meter. 1 cal equals 4.184 J, so converting between them is a matter of multiplying by that fixed factor — type any value into the converter below and both sides update instantly as you type.
Both units belong to energy, measured here against energy's base unit (J) — every other energy unit on this site converts through that same reference point, which is why the table below can also be read as a quick cross-check against nearby values.
Formula
J = cal × 4.184
cal = J × ≈0.239006
Worked example: 5 cal × 4.184 = 20.92 J.
Conversion table
| Calorie (cal) | Joule (J) |
|---|---|
| 1 cal | 4.184 J |
| 2 cal | 8.368 J |
| 3 cal | 12.552 J |
| 5 cal | 20.92 J |
| 10 cal | 41.84 J |
| 20 cal | 83.68 J |
| 25 cal | 104.6 J |
| 50 cal | 209.2 J |
| 100 cal | 418.4 J |
| 250 cal | 1,046 J |
| 500 cal | 2,092 J |
| 1,000 cal | 4,184 J |
Frequently asked
- How many Joules in a calorie?
- 1 cal equals 4.184 J.
- How do I convert Calories to Joules?
- Multiply the value in cal by 4.184 to get J. The converter above does this instantly as you type.
- Is the conversion exact?
- Yes — Calorie and Joule are both defined by a fixed conversion factor to energy's base unit (J), so the result shown is exact to the precision displayed, not an approximation.