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Energy Converter – 12 units of energy

Convert energy between kcal, kJ, kWh, J, cal, BTU and more – exact and instant.

1 kcal = 4.184 kJ

Formula: kJ = kcal × 4.184

Common values
Decimals
In every unit 12 units
Joule (J) 4,184 J
Kilojoule (kJ) 4.184 kJ
Megajoule (MJ) 0.004184 MJ
Calorie (cal) 1,000 cal
Kilocalorie (kcal) 1 kcal
Watt-hour (Wh) 1.162222222 Wh
Kilowatt-hour (kWh) 0.001162222222 kWh
Electronvolt (eV) 2.611447397 × 10²² eV
British thermal unit (BTU) 3.965666831 BTU
Therm (thm) 0.00003966613703 thm
Foot-pound (ft·lbf) 3,085.960033 ft·lbf
Erg (erg) 41,840,000,000 erg

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If you continue, the file is uploaded over an encrypted connection and converted on our server. You can keep using the site meanwhile. The original is deleted as soon as it is converted; the result is kept for 6 hours so you can download it, and you can delete it at any time. Files are never shared or used for anything else.

Calculated in your browser – nothing you type is sent anywhere. Privacy details

Units of energy

Joule (J)SI (metric) unit
Kilojoule (kJ)SI (metric) unit1 kJ = 1,000 J
Megajoule (MJ)SI (metric) unit1 MJ = 1,000,000 J
Calorie (cal)unit1 cal = 4.184 J
Kilocalorie (kcal)unit1 kcal = 4,184 J
Watt-hour (Wh)metric unit accepted with the SI1 Wh = 3,600 J
Kilowatt-hour (kWh)metric unit accepted with the SI1 kWh = 3,600,000 J
Electronvolt (eV)unit1 eV = 1.602176634 × 10⁻¹⁹ J
British thermal unit (BTU)imperial and US customary unit1 BTU = 1,055.055853 J
Therm (thm)US customary unit1 thm = 105,480,400 J
Foot-pound (ft·lbf)imperial and US customary unit1 ft·lbf = 1.355817948 J
Erg (erg)CGS unit1 erg = 1 × 10⁻⁷ J

How to use: Energy Converter

  1. 1 Pick the unit you have and the unit you need.
  2. 2 Type the value – the result in the other unit appears at once (type in the result field to convert back).
  3. 3 Use a common value, set the decimals or swap the units with one click.
  4. 4 Open “In every unit” to see the value in all 12 units of energy.

About this tool

Energy is measured in joules in science, in kilowatt-hours on electricity bills, in kilocalories on food labels and in BTU for heating and air conditioning.

Here every value is converted through the joule (J). Choose any two of the 12 units below the converter, or start from one of the popular conversions.

Calculated in your browser – nothing you type is sent anywhere.

Frequently asked questions

Which units of energy can I convert?

Joule (J), Kilojoule (kJ), Megajoule (MJ), Calorie (cal), Kilocalorie (kcal), Watt-hour (Wh), Kilowatt-hour (kWh), Electronvolt (eV), British thermal unit (BTU), Therm (thm), Foot-pound (ft·lbf) and Erg (erg).

Which energy conversions are used most?

1 kcal = 4.184 kJ; 1 kWh = 3,600,000 J; 1 cal = 4.184 J; 1 BTU = 0.0002930710702 kWh; 1 eV = 1.602176634 × 10⁻¹⁹ J; 1 kWh = 3.6 MJ.

How exact is the converter?

Each unit is defined by its official value in J, so conversions are exact up to the 10 significant digits shown; you can round to 0–6 decimals.

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