Megawatt-hours to Megajoules (MWh to MJ)

1 megawatt-hour equals 3,600 megajoules exactly.

1 megawatt-hour = 3,600 megajoules

How to convert megawatt-hours to megajoules

To convert megawatt-hours to megajoules, multiply the number of megawatt-hours by 3,600. This factor is exact. To go the other way, multiply megajoules by 0.0002777777778 (rounded).

megajoules = megawatt-hours × 3,600

Example: 10 megawatt-hours = 36,000 megajoules.

The 'calorie' on food labels is really a kilocalorie. The thermochemical calorie (4.184 J) is used here unless marked IT.

About these units

Megawatt-hour (MWh)

Metric (SI)Current unit

1,000 kilowatt-hours. Used for power-plant output and wholesale electricity trading.

A megawatt-hour is a thousand kilowatt-hours, and it is where electricity stops being a household quantity and becomes an industrial one. It is the energy of a 1 MW load running for an hour, equal to 3.6 GJ, and it is used for metering large industrial customers and for the output of power plants.

The average US household used 893 kWh a month in 2020, so one megawatt-hour is a little more than a month of an ordinary home's electricity. Scaled up further, sustaining about 114 MW for a full year amounts to one terawatt-hour, the unit used for national generation figures.

Indian usage gives a neat link: a million of what Indians call units, meaning kilowatt-hours, is a gigawatt-hour, which is 1,000 MWh. Wholesale deals, plant ratings and grid statistics are typically quoted at this scale because the numbers stay readable.

1 megawatt-hour = 3,600,000,000 joules (exactly).

Sources: Wikipedia: Kilowatt-hour; Wikipedia: Watt-hour; Wikipedia: Orders of magnitude (energy)

Megajoule (MJ)

Metric (SI)Current unit

One million joules. Used for fuel energy content and natural gas billing in many countries.

Picture a one-tonne car moving at 44.7 m/s, about 100 miles per hour: its kinetic energy is roughly one megajoule. Because the joule was originally conceived in 1882 as 10 million ergs, a megajoule is 10 to the 13th ergs, a figure that shows how little the old CGS unit suited everyday work and why the joule won out.

Food provides a more familiar benchmark. A Snickers bar of 280 food calories holds about 1.2 MJ, and a day's 2,000 food calories for a moderately active woman come to about 8.4 MJ. A kilowatt-hour of electricity is exactly 3.6 MJ, and exploding a kilogram of TNT releases about 4.2 MJ.

In other words the megajoule sits at the scale of a single serving of fuel, food or electricity, which is why it turns up in energy-content tables where joules would give unwieldy numbers.

1 megajoule = 1,000,000 joules (exactly).

Sources: Wikipedia: Joule; Wikipedia: Orders of magnitude (energy); Wikipedia: Kilowatt-hour

Related conversions

See all energy units.