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Energy Converter

Instantly convert energy between joules, kilojoules, kWh, calories, BTUs, therms, electronvolts and more.

Use a comma or period as the decimal separator; do not use thousands separators.

All units

SI

Use as target unit: Microjoule
Microjoule (µJ)
3.6e12
Use as target unit: Millijoule
Millijoule (mJ)
3,600,000,000
Use as target unit: Joule
Joule (J)
To
3,600,000
Use as target unit: Kilojoule
Kilojoule (kJ)
3,600
Use as target unit: Megajoule
Megajoule (MJ)
3.6
Use as target unit: Gigajoule
Gigajoule (GJ)
0.0036

Electrical energy

Use as target unit: Milliwatt-hour
Milliwatt-hour (mWh)
1,000,000
Use as target unit: Watt-hour
Watt-hour (Wh)
1,000
Use as target unit: Kilowatt-hour
Kilowatt-hour (kWh)
From
1
Use as target unit: Megawatt-hour
Megawatt-hour (MWh)
0.001

Calories and food energy

Use as target unit: Thermochemical Calorie
Thermochemical Calorie (cal(th))
860,421
Use as target unit: International Table Calorie
International Table Calorie (cal(IT))
859,845
Use as target unit: Thermochemical Kilocalorie
Thermochemical Kilocalorie (kcal(th))
860.421
Use as target unit: Food Kilocalorie
Food Kilocalorie (kcal(IT))
859.845

BTU and therm

Use as target unit: Thermochemical British Thermal Unit
Thermochemical British Thermal Unit (BTU(th))
3,414.43
Use as target unit: British Thermal Unit (International Table)
British Thermal Unit (International Table) (BTU(IT))
3,412.14
Use as target unit: US Therm
US Therm (therm(US))
0.0341214

Mechanical and CGS units

Use as target unit: Erg
Erg (erg)
3.6e13
Use as target unit: Inch-pound Force
Inch-pound Force (in·lbf)
31,862,700
Use as target unit: Foot-pound Force
Foot-pound Force (ft·lbf)
2,655,220

Particle energy

Use as target unit: Electronvolt
Electronvolt (eV)
2.24694e25
Use as target unit: Kiloelectronvolt
Kiloelectronvolt (keV)
2.24694e22
Use as target unit: Megaelectronvolt
Megaelectronvolt (MeV)
2.24694e19
Use as target unit: Gigaelectronvolt
Gigaelectronvolt (GeV)
2.24694e16

Energy equivalents

Use as target unit: Ton of TNT Equivalent
Ton of TNT Equivalent (t TNT)
0.000860421
Use as target unit: Tonne of Oil Equivalent
Tonne of Oil Equivalent (toe)
0.0000859845
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Good to know

The energy converter converts directly in your browser between SI, electrical, calorie, BTU/therm, mechanical/CGS, and particle-energy units, via a common joule base. cal(th), cal(IT), BTU(IT), and BTU(th) are deliberately kept separate, since they have slightly different definitions.

Typical searches include kWh to joules, calories to kilojoules, and convert energy. Calculation runs locally in the browser. Energy and power are different quantities: kWh is energy, kW is power. Nutrition calories, technical energy, and electricity costs also have different contexts and shouldn't be mixed.

Typical use cases

Convert electricity consumption into joules

Convert kWh from electricity bills into joules or other energy units for technical calculations.

Convert nutrition figures between calories and kilojoules

Convert nutrition calories into kilojoules to compare packaging labels from different countries.

Tips for better results

Don't confuse kWh with kW

kWh is a unit of energy, kW a unit of power — both frequently appear together on electricity bills and are easily confused.

Choose the correct calorie/BTU definition

cal(th), cal(IT), BTU(IT), and BTU(th) differ slightly — choose the definition matching your source for exact results.

How it works

Step by step

  1. 1

    Enter value and source unit

    Enter the energy value and choose the source unit from one of the six groups.

  2. 2

    Choose the target unit

    Choose the target unit, even from a different group, for example from kWh to joules.

  3. 3

    Copy the result

    Copy one or all results for further use.

Features

Six unit groups

SI, mechanical/CGS, electrical, calorie/nutrition, BTU/therm, and particle energy are separated.

Local conversion

Calculation happens directly in the browser, without transmission to a server.

Separate calorie and BTU definitions

cal(th), cal(IT), BTU(IT), and BTU(th) are clearly distinguished instead of mixed together.

Frequently asked questions

Are kWh and kW the same?

No. kWh is a unit of energy, kW a unit of power. This converter converts energy units exclusively.

Are my inputs uploaded?

No. Conversion runs entirely locally in the browser.

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