Kilojoules to Kilocalories

Convert kilojoules (kJ) to kilocalories (kcal). Type a value below to see the result update instantly. Reference table and formula included.

Calculator

Kilojoules

⇌

Kilocalories

kcal

1 kJ = 0.239006 kcal

Kilojoules to Kilocalories Conversion Table

Common values, ready to copy:

kilojoules	kilocalories
1 kJ	0.239006 kcal
2 kJ	0.478011 kcal
5 kJ	1.195 kcal
10 kJ	2.3901 kcal
25 kJ	5.9751 kcal
50 kJ	11.9503 kcal
100 kJ	23.9006 kcal
1,000 kJ	239.01 kcal

Formula

kilocalories = kilojoules × 2.39005736e-1

Energy uses the SI joule. Food calories (kcal) are 1,000 small calories: 1 kcal = 4,184 J. 1 kWh = 3.6 MJ = 3,600,000 J. 1 BTU = 1,055.06 J.

About Kilojoules and Kilocalories

Kilojoules (kJ): A thousand joules; the practical SI energy unit for food and nutrition in metric countries. Common uses: Food energy labeling outside the US, electrical energy in kJ for small batteries, and biology (metabolism).

Kilocalories (kcal): A thousand small calories, or about 4,184 J; this is what 'calories' means on US food labels. Common uses: Food energy labeling in the US (a 'Calorie' on a US food label is a kilocalorie), nutrition tracking, and exercise energy expenditure.

How the conversion works

Energy uses the SI joule. Food calories (kcal) are 1,000 small calories: 1 kcal = 4,184 J. 1 kWh = 3.6 MJ = 3,600,000 J. 1 BTU = 1,055.06 J.

The exact relationship is kilocalories = kilojoules × 2.39005736e-1, which the calculator at the top of this page applies in both directions. Type into either field and the other updates immediately.

When this conversion matters

Converting between kilojoules and kilocalories comes up wherever energy measurements move between systems — from one country's conventions to another's, from a scientific reference to a practical specification, or from one industry's working unit to another's. The calculator and reference table above cover the everyday range; for unusual values you can type any number into either field.