Calories to kilojoules
Type a value in calories to see it in kilojoules straight away, or type in the second box to convert back.
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How to use it
- Type the value in the calories box.
- Read the result in kilojoules as you type, and pick the precision you need.
- Swap the direction to convert back, or copy the result.
How it is calculated
kJ = cal × 0.004184
Multiply the value in calories by 0.004184 to get kilojoules.
Example
To convert 25 cal to kilojoules: 25 × 0.004184 = 0.1046 kJ.
Conversion table
| Calories (cal) | Kilojoules (kJ) |
|---|---|
| 1 | 0.004184 |
| 2 | 0.008368 |
| 3 | 0.012552 |
| 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 the units
- Calorie
- The small calorie in its thermochemical definition, exactly 4.184 joules. The food calorie on labels equals 1000 of these.
- Kilojoule
- Exactly 1000 joules. It appears on food labels next to the calorie figure.
Limits and caveats
- Results are rounded for display and computed with the browser's floating point precision (about 15 significant digits).
- Both unit factors are exact by their official definitions.
Questions about this tool
How many kilojoules are in one calorie?
1 cal = 0.004184 kJ exactly.
How do I convert calories to kilojoules?
Use kJ = cal × 0.004184. For example, 25 cal = 0.1046 kJ.
How many calories are in one kilojoule?
1 kJ = 239.006 cal.
Which calorie do these converters use?
The thermochemical calorie, exactly 4.184 joules, the factor many countries use to turn kcal into kJ on food labels. The International Table calorie is 4.1868 joules, less than 0.07% larger.
What is the difference between kW and kWh?
A kilowatt is a unit of power, the rate of using energy, while a kilowatt-hour is an amount of energy. A 2 kW heater running for three hours uses 6 kWh.