Free kJ to kcal calculator

kilojoules to kilocalories converter

Convert energy from kilojoules to kilocalories for nutrition labels, exercise estimates, and energy comparisons.

Updated July 20, 2026 Method and assumptions shown below

Convert kilojoules to kilocalories

Enter any value to calculate the result instantly.

kilojoules to kilocalories formula

Divide kilojoules by exactly 4.184. One thermochemical kilocalorie equals 4.184 kilojoules.

kilocalories = kilojoules / 4.184

Conversion table

Use these reference values for a quick comparison. The calculator above accepts positive, negative, decimal, and large values when they are meaningful for the quantity.

kilojouleskilocalories
100 kJ23.90057361 kcal
250 kJ59.75143403 kcal
500 kJ119.5028681 kcal
1,000 kJ239.0057361 kcal
2,000 kJ478.0114722 kcal
2,500 kJ597.5143403 kcal

How to use this converter

Enter the source measurement in the first field. CalUnit applies the displayed formula and updates the destination value immediately. You can use decimals and negative values, copy the result into your work, and compare it with the reference table. Keep the original unit beside the starting measurement so another reader can verify the calculation. For a different unit pair, open the complete energy conversion guide or the multi-unit energy converter.

When this conversion is useful

On food labels, a capital-C Calorie normally means one kilocalorie. Nutrition values are estimates and can be rounded under regional labeling rules.

Accuracy and rounding

The thermochemical conversion factor is exact. Food energy and exercise expenditure figures have much larger practical uncertainty than the unit conversion.

Standards references

CalUnit checks physical unit relationships against authoritative measurement references. See the NIST Guide to the SI conversion factors and the BIPM SI Brochure. Regional cooking measures and digital storage conventions are identified separately because their names can represent more than one definition.