Kilocalories to kilojoules (kcal to kJ)
Convert kilocalories to kilojoules. For energy, 1 kcal equals 4.184 kJ.
Converter
kcal to kJ conversion table
| Kilocalories | Kilojoules |
|---|---|
| 1 kcal | 4.184 kJ |
| 2 kcal | 8.368 kJ |
| 5 kcal | 20.92 kJ |
| 10 kcal | 41.84 kJ |
| 25 kcal | 104.6 kJ |
| 50 kcal | 209.2 kJ |
| 100 kcal | 418.4 kJ |
| 1000 kcal | 4184 kJ |
Formula
kJ = kcal × 4.184
Worked example
25 kcal × 4.184 = 104.6 kJ
Popular conversion examples
Choose an example to open this converter with the value filled in. These are useful examples, not a claim about search rankings.
- 1 kcal to kJ = 4.184 kJ
- 5 kcal to kJ = 20.92 kJ
- 100 kcal to kJ = 418.4 kJ
- 10 kcal to kJ = 41.84 kJ
- 400 kJ to kcal = 95.6023 kcal
- 8302 kJ to kcal = 1984.23 kcal
About kilocalories and kilojoules
Kilocalorie (kcal)
A kilocalorie is 1,000 thermochemical calories, or 4,184 joules. It is the unit people mean by “Calories” on food labels.
Kilojoule (kJ)
A kilojoule is 1,000 joules. It is used for food energy in many countries and for heat and work in engineering.
Both are units of energy; the base unit used internally is J.
Notes
- Calorie = thermochemical calorie (4.184 J); kilocalorie = 1000 cal (the food “Calorie”).
- BTU = International Table BTU (1055.05585262 J). Other BTU definitions (thermochemical, 39 °F, etc.) differ slightly and are not included.
- Energy is not power: a kilowatt-hour is an amount of energy, a kilowatt is a rate.
kcal to kJ FAQs
How do I convert kilocalories to kilojoules?
Multiply the number of kilocalories by 4.184 to get kilojoules. For example, 25 kcal × 4.184 = 104.6 kJ.
How many kilojoules are in one kilocalorie?
1 kcal = 4.184 kJ and 1 kJ = 0.2390057361 kcal. To go the other way, use the kilojoules to kilocalories converter.
How many kilojoules are in 1000 kilocalories?
1000 kcal = 4184 kJ, rounded to 6 significant digits. Change the value in the converter above for any other amount.
How many kilojoules are in 300 kilocalories?
300 kcal = 1255.2 kJ, rounded to 6 significant digits.
Is the kcal to kJ conversion exact?
Yes. The factor 4.184 follows directly from the unit definitions (A kilocalorie is 1,000 thermochemical calories, or 4,184 joules; a kilojoule is 1,000 joules), so the only rounding is in the digits you choose to display.
What is the difference between kilocalories and kilojoules?
A kilocalorie is 1,000 thermochemical calories, or 4,184 joules. It is the unit people mean by “Calories” on food labels. A kilojoule is 1,000 joules. It is used for food energy in many countries and for heat and work in engineering.
What is the difference between a calorie and a Calorie?
The calorie (cal) is 4.184 joules. The “Calorie” on food labels is a kilocalorie (kcal): 1 kcal = 1,000 cal = 4184 J.
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Guide
Read: Calories vs Kilocalories (kcal vs cal).