How many kWh in 1 joule?

1 J = approximately 0.000000278 kWh (2.778 × 10⁻⁷ kWh). To put this in perspective, a 100 W light bulb uses 1 joule every 0.01 seconds.

How do I convert joules to kWh without a calculator?

Divide by 3.6 million. For example, 7.2 MJ ÷ 3.6 million = 2 kWh. Memorise the factor: 1 kWh = 3.6 MJ.

A household using 30 kWh per day consumes 30 × 3,600,000 = 108,000,000 J (108 MJ) daily. Expressed in kWh, the bill is more readable.

1 J = 2.778×10⁻⁷ kWh. Divide joules by 3,600,000 to convert to kilowatt-hours. 1 MJ = 0.2778 kWh.

Inverse conversion

1 kWh = 3,600,000 J. Multiply kilowatt-hours by 3,600,000 (3.6 million) to get joules. 10 kWh = 36 MJ.

kWh = J ÷ 3,600,000

Worked example

To convert 18,000,000 J to kWh: 18,000,000 ÷ 3,600,000 = 5 kWh.

Joule (J)

The joule (J) is the SI unit of energy. It equals the work done by a force of 1 newton over 1 metre.

Kilowatt-hour (kWh)

A kilowatt-hour (kWh) equals 3,600,000 joules. It is the commercial unit for measuring electrical energy consumption.