Energy Converter (J, kWh, kcal, BTU)

Enter a value and pick units — the conversion updates instantly.

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ValueFromTo

Show all units

How to use

Type a number in “Value” and choose the units to convert from and to. The page opens on kWh → MJ.
The arrow button in the middle swaps the two units.
“Show all units” lists the same energy in kcal, BTU, eV and every other unit. Very large or tiny values appear in exponent form, such as 1.6e-19.
The page address keeps your value and units, so you can share the link as is.

How many joules are in a kilowatt-hour?

3,600,000 J (3.6 MJ) — the energy a 1 kW appliance uses in one hour, or roughly 860 kcal.

Which calorie does this tool use?

The thermochemical calorie: 1 cal = 4.184 J, so 1 kcal = 4.184 kJ. The International Table calorie (4.1868 J) differs by about 0.07%.

How many kWh are in a therm?

A therm is 100,000 BTU, about 29.31 kWh. US natural gas bills are often charged per therm.

What is an electronvolt?

The energy an electron gains crossing 1 volt: 1.602176634 × 10⁻¹⁹ J. It is the everyday unit of atomic and particle physics.