kcal to kJ Converter - Kilocalorie to Kilojoule
Kilocalorie (kcal) to Kilojoule (kJ)
Direct answer
1 kcal = 4.184 kJ
kJ = kcal × 4.184
Converter
Conversion formula
kJ = kcal × 4.184
kcal = kJ × 0.239005736138
Example: 10 kcal = 10 × 4.184 = 41.84 kJ.
Common conversion table
| kcal | kJ |
|---|---|
| 1 kcal | 4.184 kJ |
| 2 kcal | 8.368 kJ |
| 5 kcal | 20.92 kJ |
| 10 kcal | 41.84 kJ |
| 20 kcal | 83.68 kJ |
| 50 kcal | 209.2 kJ |
| 100 kcal | 418.4 kJ |
| 1,000 kcal | 4,184 kJ |
Conversion derivation
Express both kcal and kJ in the same base unit J (joule), then cancel the shared base unit.
- 1
Rewrite kcal in the base unit
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Rewrite kJ in the base unit
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Forward conversion
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Reverse conversion
AI explanation for this conversion
This pre-generated explanation is schema-checked. Numeric results still come from the page formula and calculator.
Kilocalorie to Kilojoule Conversion
The conversion factor from kilocalories (kcal) to kilojoules (kJ) is 4.184. This factor arises because one kilocalorie is defined as exactly 4,184 joules, and one kilojoule is defined as exactly 1,000 joules.
Definition
A kilocalorie (kcal) is a unit of energy equal to 1,000 calories, and a kilojoule (kJ) is a unit of energy equal to 1,000 joules. The joule is the SI base unit of energy.
Principle
The conversion works by expressing both units in terms of the shared base unit, the joule. Dividing the number of joules in one kilocalorie (4,184 J) by the number of joules in one kilojoule (1,000 J) yields the direct conversion factor.
Assumptions
- The definitions used are the standard nutritional (thermochemical) calorie, where 1 kcal = 4,184 J exactly.
- The units are being used in a context where this specific calorie definition applies.
Cautions
- Different definitions of the calorie exist (e.g., the international steam table calorie), which would lead to a different conversion factor.
- The conversion factor is exact based on the given definitions; any rounding in calculations is a separate step.
FAQ
How many kJ are in 1 kcal?
1 kcal = 4.184 kJ.
How many kJ are in 10 kcal?
10 kcal = 41.84 kJ.
How many kJ are in 100 kcal?
100 kcal = 418.4 kJ.
What is the formula to convert kcal to kJ?
Use kJ = kcal × 4.184.
How many kcal are in 1 kJ?
1 kJ = 0.239005736138 kcal.
What should I check when converting kcal to kJ?
Use the conversion factor and round the result to the precision required by your calculation.