Calories to Joules Converter
1 calorie = 4.184 joules
This is the small calorie. The "Calorie" on food labels is a kilocalorie, which is 1,000 of these.
1 calorie equals 4.184 joules
How to convert calories to joules
Calories here are thermochemical (4.184 J), while BTU uses the International Table definition. A kilowatt-hour is energy (3.6 MJ), not power; a food Calorie is a kilocalorie.
J = cal × 4.184One calorie is 4.184 joules, so a single multiplication converts any value.
41.84 J = 10 × 4.184This is the small calorie. The "Calorie" on food labels is a kilocalorie, which is 1,000 of these.
Calories to joules conversion table
Common values in calories, converted to joules.
| Calories (cal) | Joules (J) |
|---|---|
| 1 | 4.184 |
| 2 | 8.368 |
| 3 | 12.552 |
| 4 | 16.736 |
| 5 | 20.92 |
| 10 | 41.84 |
| 20 | 83.68 |
| 25 | 104.6 |
| 50 | 209.2 |
| 100 | 418.4 |
| 250 | 1,046 |
| 500 | 2,092 |
| 1,000 | 4,184 |
About these units
caloriecal
The thermochemical calorie: exactly 4.184 joules.
Reference: NIST Special Publication 811.
jouleJ
The SI derived unit of energy: one newton acting through one metre.
Sources and precision
Table results are rounded to 8 significant digits; formula constants may be rounded to 10. Worked example answers use 6 significant digits. The converter starts at 6 significant digits and lets you change display precision. Calculations use the stored factors without intermediate rounding. Exact unit definitions do not make an input measurement more precise; conventional and measured factors follow the assumptions stated here.