Convert Kilowatt-hours to Joules

About converting Kilowatt-hours to Joules

Kilowatt-hours (kWh) and Joules (J) are both units of energy, so converting between them is a single multiplication: multiply your Kilowatt-hours figure by 3,600,000. Ten Kilowatt-hours comes to 36,000,000 Joules, and a hundred works out at 360,000,000 Joules.

Rule of thumb: going from Kilowatt-hours to Joules multiplies, so the figure always grows — one Kilowatt-hour is already 3,600,000 Joules. If your answer came out smaller, you have the conversion the wrong way round.

What is a Kilowatt-hour?

The kilowatt-hour is the unit your electricity bill is charged in, and almost the only energy unit most people meet by name. It is energy, not power: a kilowatt is a rate of use, a kilowatt-hour is the amount consumed by running at that rate for an hour. Utilities bill in kWh because that is what they actually deliver — a meter counts accumulated energy, not instantaneous demand. It is also the unit that sizes batteries. An EV pack and a home storage unit are both quoted in kilowatt-hours, so the figure tells you how much range or backup you have bought, while the kilowatt rating only says how fast it can be delivered.

What is a Joule?

The joule is the SI unit of energy and the reference every other energy unit here is defined against. One joule is one newton acting over one metre — push with a newton of force, move a metre, and you have spent a joule. It is named after James Prescott Joule, whose painstaking experiments established that heat and mechanical work are the same thing, measurable in the same units. That result sounds obvious now and was foundational then: it collapsed heat, motion and work into a single quantity called energy, which is why one unit can serve food, electricity, explosives and engines alike.

To put both in perspective: an electric car covers roughly five kilometres on a kilowatt-hour, while lifting an apple one metre takes about a joule.

The converter above updates as you type, and the table lists common values for quick reference. Need the opposite direction? Use the Joules to Kilowatt-hours converter, or browse all Energy converters.