Skip to content
Toolore

Converters

Energy Converter

Convert energy for food labels, electricity bills and heating. One thing worth knowing before you start: the “calorie” on a food label is really a kilocalorie, one thousand of the scientific calories used in physics.

kilojoules to kilocalories

0.239 kcal

1 kJ converted

1 kJ equals
0.239 kcal
Conversion factor
Exact by definition

Worth knowing

  • The 'calorie' on food labels is a kilocalorie (kcal), one thousand of the scientific calories used here.

How to use this tool

  1. Enter the amount of energy.
  2. Choose your units. Use kilocalories for food-label calories.

Worked examples

A 250 kcal snack in kilojoules

  1. 250 × 4184 = 1,046,000 J
  2. 1,046,000 ÷ 1000 = 1046

1,046 kJ — which is what an EU food label would show.

Notes and limitations

  • A food 'Calorie' with a capital C is a kilocalorie: 1,000 scientific calories. European labels avoid the confusion by using kilojoules.
  • A kilowatt hour is 3.6 million joules. It is a unit of energy, not power — a 2 kW heater running for 30 minutes uses 1 kWh.
  • The BTU used here is the International Table BTU. Several slightly different BTU definitions exist, differing by a fraction of a percent.
  • The calorie here is the thermochemical calorie of exactly 4.184 J, which is the definition used on nutrition labels.

Frequently asked questions

How many kilojoules are in a calorie?

A food calorie (kcal) is 4.184 kilojoules. So a 2,000 kcal daily intake is about 8,368 kJ.

What is the difference between a calorie and a Calorie?

A lowercase calorie is the physics unit, 4.184 joules. A capitalised Calorie on food packaging is a kilocalorie, a thousand times larger. Nutrition labels almost always mean the larger one.

How many joules are in a kilowatt hour?

3,600,000. A kilowatt is 1,000 joules per second, and an hour is 3,600 seconds.

Related tools