⚡ Calorie to Joule Converter
1 calorie = 4.184 joules. Convert between calories and joules for nutrition, physics and chemistry calculations.
1 cal=4.184 J
Quick Reference: Calorie → Joule
| cal | J |
|---|---|
| 0.5 | 2.092 |
| 1 | 4.184 |
| 2 | 8.368 |
| 3 | 12.552 |
| 5 | 20.92 |
| 10 | 41.84 |
| 25 | 104.6 |
| 50 | 209.2 |
| 100 | 418.4 |
About this conversion
The calorie is the historical unit of heat energy; the joule is the SI unit. The two are related by the exact factor 1 cal = 4.184 J, defined in 1929 to align thermochemistry with mechanics.
Formula
J = cal × 4.184. Conversely, cal = J / 4.184.
Worked example
500 calories of heat = 500 × 4.184 = 2,092 joules.
History & background
The thermochemical calorie was defined by the International Steam Table in the late 1920s. Today the joule is preferred in scientific publications, while the calorie persists in nutrition (where 1 nutritional "Calorie" actually means 1 kilocalorie).
Common use cases
- Physics and chemistry homework
- Comparing energy values in research papers
- Converting old engineering tables to SI
Frequently Asked Questions
How many joules in 1 calorie?+
Exactly 4.184 joules (thermochemical definition).
Is the food Calorie the same as a calorie?+
No — 1 food "Calorie" with a capital C equals 1,000 small calories, or 4,184 joules.
Why two definitions of the calorie?+
The "international" calorie (4.1868 J) and the "thermochemical" calorie (4.184 J) differ by ~0.02%. We use the thermochemical value.