Kilocalories to Megajoules

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

Calculator

Kilocalories

kcal

⇌

Megajoules

1 kcal = 0.004184 MJ

Kilocalories to Megajoules Conversion Table

Common values, ready to copy:

kilocalories	megajoules
1 kcal	0.004184 MJ
2 kcal	0.008368 MJ
5 kcal	0.02092 MJ
10 kcal	0.04184 MJ
25 kcal	0.1046 MJ
50 kcal	0.2092 MJ
100 kcal	0.4184 MJ
1,000 kcal	4.184 MJ

Formula

megajoules = kilocalories × 0.004184

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 Kilocalories and Megajoules

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.

Megajoules (MJ): A million joules; the unit for larger-scale energy quantities. Common uses: Daily food intake (a typical adult consumes 8-10 MJ per day), fuel energy content (gasoline ≈ 34 MJ per liter), and industrial energy.

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 megajoules = kilocalories × 0.004184, 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 kilocalories and megajoules 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.