How to use

Convert energy units used in physics, electricity and heat through the joule as a common base. The tool includes J, kJ, MJ, Wh, kWh, thermochemical calories, kilocalories, BTU, electronvolts and foot-pounds.

Enter the energy amount and source unit.
Choose the target unit.
Read the converted value plus quick equivalents in joules, kWh, kcal and BTU.

How it is calculated

Convert through joules; 1 kWh = 3,600,000 J and 1 thermochemical kcal = 4,184 J

Example

Example: 1 kWh = 3,600,000 J ≈ 860.4206501 kcal ≈ 3,412.141633 BTU. A kilowatt-hour is energy; a kilowatt by itself is power, not energy.

Important notes

The cal and kcal units here use the thermochemical definition: 1 cal = 4.184 J and 1 kcal = 4,184 J. A food-label Calorie usually means one kilocalorie. Energy cannot be converted to power without a time interval because power = energy ÷ time.

Frequently asked questions

How many joules are in 1 kWh?

Exactly 3,600,000 joules.

Is a kcal the same as a food Calorie?

In nutrition, a capital-C Calorie usually means one kilocalorie, equal to 4,184 J.

Can kWh be converted directly to kW?

No. kWh is energy and kW is power; a time interval is required.

Is this calculator free?

Yes. It is free to use and requires no account.

Energy Converter