Convert Kilowatt-Hour to Megajoule (kWh → MJ)

Converting kilowatt-hours to megajoules is straightforward: multiply by the conversion factor. Follow these three steps to do it by hand or in your head.

1. 1
   Take your value in kilowatt-hours

   Start with the number of kilowatt-hours (kWh) you want to convert.
2. 2
   Multiply by 3.6

   The conversion factor from kWh to MJ is 3.6. Multiply your value by this number.
3. 3
   Read the result in megajoules

   The result is your value in megajoules (MJ).

Multiply the value in kilowatt-hours by 3.6. For the reverse direction, multiply by 0.277778.

• ✓1 kWh = 3.6 MJ = 3,600,000 J.
• ✓Multiply device power (kW) × time (h) = energy (kWh).
• ✓EV "range anxiety" translates to knowing kWh available.

• ✗Confusing kWh (energy) with kW (power).
• ✗Calculating electric costs by power ignoring duration.
• ✗Using "kWh/h" — redundant; it's just kW.

What is the Kilowatt-Hour?

The kilowatt-hour equals 1,000 watt-hours (3.6 megajoules) and is the universal billing unit for residential electricity consumption around the world. A typical US household uses about 800–1,000 kWh per month; a refrigerator consumes 1–2 kWh per day, an LED bulb at 10 W for 10 hours uses 0.1 kWh, and a Tesla Model 3 has a 75 kWh battery (about 250–350 miles of range). Electric utility rates are quoted in cents per kWh — typical US residential rates are 11–25 ¢/kWh, while industrial rates are lower. The kilowatt-hour is essential in renewable-energy planning: solar panel output, wind farm production, and grid-scale storage are all rated in kWh or MWh (megawatt-hours). It relates to the watt-hour (1,000 Wh = 1 kWh), the joule (1 kWh = 3.6 MJ), the BTU (1 kWh ≈ 3,412 BTU), and the megawatt-hour (1,000 kWh = 1 MWh).

• Electricity billing globally
• EV battery capacity specifications
• Home solar and battery storage

What is the Megajoule?

The megajoule equals 1,000,000 joules (or 1,000 kilojoules) and is used for measuring fuel energy content, large-scale electrical work, and industrial heat applications. The energy content of food and fuel is often quoted in MJ: a kilogram of gasoline contains about 46 MJ, natural gas has 38 MJ per cubic meter, and a kilogram of coal yields 24 MJ. Vehicle fuel-economy and energy-efficiency calculations use MJ to compare disparate energy sources. Industrial process heating, boiler outputs, and large machinery energy ratings are commonly given in MJ per cycle or MJ per hour. The megajoule relates to the joule (10⁶ J = 1 MJ), the kilojoule (1,000 kJ = 1 MJ), the kilowatt-hour (1 kWh = 3.6 MJ), and the BTU (1 MJ ≈ 948 BTU). For electricity-grid energy accounting, the equivalent kilowatt-hour or megawatt-hour is more common than MJ.

• Fuel energy content reporting
• Natural gas billing in some countries
• Industrial energy consumption