Energy Converter

Convert energy for food labels, electricity bills, heating and science.

From

1 kilocalorie = 4.184 kilojoules

Formula: kJ = kcal × 4.184

The same amount in other units

Unit	Value
Joule (J)	4,184
Kilojoule (kJ)	4.184
Calorie (cal)	1,000
Kilocalorie (kcal)	1
Watt-hour (Wh)	1.162222222
Kilowatt-hour (kWh)	0.001162222222
British thermal unit (BTU)	3.965666831
Electronvolt (eV)	2.61145E22

Popular conversions

From food labels to electricity bills

The SI unit of energy is the joule. Food energy is usually given in kilocalories, which food labels call Calories with a capital C, and in kilojoules in many countries. One kilocalorie is exactly 4.184 kilojoules.

Electricity is billed in kilowatt-hours. One kilowatt-hour is the energy a 1,000-watt appliance uses in one hour, exactly 3.6 megajoules. Heating and air-conditioning equipment in the United States is rated in British thermal units (BTU).

Units in this converter

Joule (J): The SI unit of energy, the work done by a force of one newton over one meter.
Kilojoule (kJ): 1,000 joules. Food labels in many countries show energy in kJ alongside kcal.
Calorie (cal): Exactly 4.184 joules (the thermochemical calorie). The food Calorie is actually a kilocalorie.
Kilocalorie (kcal): 1,000 calories, exactly 4.184 kJ. This is the Calorie shown on food labels.
Watt-hour (Wh): 3,600 joules, the energy of 1 watt for 1 hour. Used for battery capacity.
Kilowatt-hour (kWh): Exactly 3.6 megajoules. The unit on electricity bills.
British thermal unit (BTU): About 1,055 joules. Used for heating and air-conditioner ratings in the United States.
Electronvolt (eV): Exactly 1.602176634 × 10⁻¹⁹ joules. Used in physics for the energy of particles.

Frequently asked questions

Is a food Calorie the same as a calorie?

No. The Calorie on food labels is a kilocalorie, 1,000 small calories. So a snack with 200 Calories contains 200 kcal, or about 837 kJ.