Calories to Kilojoules Converter
1 calorie = 0.004184 kilojoules
This is the small calorie. The "Calorie" on food labels is a kilocalorie, which is 1,000 of these.
1 calorie equals 0.004184 kilojoules
How to convert calories to kilojoules
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.
kJ = cal × 0.004184One calorie is 0.004184 kilojoules, so a single multiplication converts any value.
0.04184 kJ = 10 × 0.004184This is the small calorie. The "Calorie" on food labels is a kilocalorie, which is 1,000 of these.
Calories to kilojoules conversion table
Common values in calories, converted to kilojoules.
| Calories (cal) | Kilojoules (kJ) |
|---|---|
| 1 | 0.004184 |
| 2 | 0.008368 |
| 3 | 0.012552 |
| 4 | 0.016736 |
| 5 | 0.02092 |
| 10 | 0.04184 |
| 20 | 0.08368 |
| 25 | 0.1046 |
| 50 | 0.2092 |
| 100 | 0.4184 |
| 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.
kilojoulekJ
One thousand joules. The metric food-energy unit outside the United States.
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.