FREE ONLINE CONVERTER

Calories to Kilojoules Converter (kcal to kJ)

Convert calories to kilojoules instantly with our free kcal to kJ calculator. Enter a value to see the result.

Result1 kcal = 4.184 kJ
⇄ Switch to Kilojoules to Calories
Quick answer: 1 calories (kcal) = 4.184 kilojoules (kJ).

How to convert calories to kilojoules

To change kcal into kJ, use this formula:

kJ = kcal × 4.184

Quick mental estimate: multiply by about 4.2.

Example: to convert 25 kcal to kJ, calculate 104.6 kJ. To go the other way, use kcal = kJ ÷ 4.184.

Popular calories to kilojoules conversions

Calories to Kilojoules conversion chart

Calories (kcal)Kilojoules (kJ)
1 kcal4.184 kJ
2 kcal8.368 kJ
5 kcal20.92 kJ
10 kcal41.84 kJ
20 kcal83.68 kJ
25 kcal104.6 kJ
50 kcal209.2 kJ
75 kcal313.8 kJ
100 kcal418.4 kJ
250 kcal1,046 kJ
500 kcal2,092 kJ
1,000 kcal4,184 kJ

When do you need kcal to kJ conversion?

This conversion is commonly used for nutrition, electricity bills and physics. Different countries and industries use different units, so converting calories to kilojoules helps you compare measurements accurately.

Frequently asked questions

How many kilojoules are in 1 calories?

1 kcal equals 4.184 kJ.

How do I convert calories to kilojoules?

Use the formula kJ = kcal × 4.184. For example, 25 kcal = 104.6 kJ.

What is 10 kcal in kJ?

10 kcal = 41.84 kJ.

What is 100 kcal in kJ?

100 kcal = 418.4 kJ.

How do I convert kJ back to kcal?

Use kcal = kJ ÷ 4.184. You can also use our Kilojoules to Calories converter.

Is this kcal to kJ converter accurate?

Yes. It uses standard international conversion factors and shows up to 6 significant digits.

Related energy converters

All energy converters → · All converters →