How kilocalories and kilojoules are converted
200 kcal = 836.8 kJ. In reverse, 418.4 kJ = 100 kcal.
kilojoules = kilocalories × 4.184; kilocalories = kilojoules ÷ 4.184
- Multiply kilocalories by 4.184 to find kilojoules.
- Reverse the calculation to convert kilojoules back to kilocalories.
- Only the displayed values are rounded. The conversion uses the full unit factor.
Worked example: 200 kcal = 836.8 kJ. In reverse, 418.4 kJ = 100 kcal.
Common kilocalories to kilojoules values
| Kilocalories | Kilojoules (kJ) |
|---|---|
| 1 kcal | 4.184 kJ |
| 10 kcal | 41.84 kJ |
| 100 kcal | 418.4 kJ |
| 200 kcal | 836.8 kJ |
| 1,000 kcal | 4,184 kJ |
| 2,000 kcal | 8,368 kJ |
Swipe the table sideways to see the rest.
Results use the same exact factors as the calculator.
Things to consider
- Check whether a food label uses kcal or kJ before comparing values.
- One dietary Calorie is one kilocalorie, equal to 4.184 kJ.
- Power in kilowatts needs a duration in hours to calculate energy in kWh.
- Negative amounts can represent an energy change, such as heat leaving a system.
Frequently asked questions
How do I convert kilocalories to kilojoules?
Multiply by 4.184. 200 kcal = 836.8 kJ. In reverse, 418.4 kJ = 100 kcal.
Can I convert kilojoules back to kilocalories?
Yes. Choose the reverse direction. Divide by 4.184.
Are food Calories the same as small calories?
No. A food Calorie means one kilocalorie (kcal), equal to 1,000 small calories (cal). This converter uses thermochemical calories: 1 kcal = 4.184 kJ.
Is a kilowatt-hour the same as a kilowatt?
No. Kilowatts measure power. Kilowatt-hours measure energy. At constant power, 1 kW for 1 hour uses 1 kWh.
Results are estimates for general information only, not financial, medical or professional advice.