Kilocalories to kilojoules
Multiply kilocalories by 4.184 to get kilojoules.
250 kcal = 1,046 kJ
How to convert kilocalories to kilojoules
The kilojoule is one thousand joules — the metric food-energy unit used outside the US. The kilocalorie is one thousand thermochemical calories (4184 J) — the "Calorie" on food labels.
Worked example — 250 kcal: 250 × 4.184 = 1,046 kJ.
Kilocalories to kilojoules table
| Kilocalories | Kilojoules |
|---|---|
| 1 kcal | 4.184 kJ |
| 50 kcal | 209.2 kJ |
| 100 kcal | 418.4 kJ |
| 200 kcal | 836.8 kJ |
| 250 kcal | 1,046 kJ |
| 500 kcal | 2,092 kJ |
| 1,000 kcal | 4,184 kJ |
| 1,500 kcal | 6,276 kJ |
| 2,000 kcal | 8,368 kJ |
Reverse and related
About kilocalories and kilojoules
Kilocalorie (kcal)
1 kcal = 4.184 kJDefinition. One thousand thermochemical calories (4184 J) — the "Calorie" on food labels
History and origin
The kilocalorie is one thousand calories, where the calorie was defined as the heat needed to warm one gram of water by one degree Celsius. On food labels the capitalised Calorie is really a kilocalorie.
Current use
Kilocalories, shown as Calories, measure food energy on US and many other nutrition labels.
Source: NIST SP 811, Appendix B; ISO 80000-5 (energy)
Kilojoule (kJ)
1 kJ = 0.239006 kcalDefinition. One thousand joules — the metric food-energy unit used outside the US
History and origin
The kilojoule is one thousand joules, the metric unit of energy built on the SI joule. It is the food-energy unit preferred where the metric system is standard.
Current use
Kilojoules are used on nutrition labels outside the United States and throughout physics and engineering.
Source: NIST SP 811, Appendix B; ISO 80000-5 (energy)
Where people use this
Kilocalories: nutrition and diet, food labels. Kilojoules: nutrition labels outside the US, physics. A 250 kcal snack is about 1046 kJ.
Every value is carried to full double precision; the display is rounded.
Both units are defined in NIST SP 811, Appendix B; ISO 80000-5 (energy).
Questions people ask
How many kJ is 250 kcal?
A 250 kcal snack is about 1046 kJ. To convert kcal to kJ, multiply by 4.184.
How many kJ in a Calorie?
One food Calorie, which is a kilocalorie, is about 4.184 kJ.
How many kJ is 2000 kcal?
A 2000 kcal daily intake is about 8368 kJ, close to the 8400 kJ often quoted.
Are food Calories the same as kcal?
Yes. The Calorie on nutrition labels is a kilocalorie, so 100 Cal is 100 kcal, or about 418 kJ.