Energy & Power

Kilowatt-hours to Megajoules

Convert kilowatt-hours to megajoules instantly. 1 kWh = 3.6 MJ. Includes the exact factor, a conversion table of common values and the definition of both units.

kWh
Megajoules
One step, one exact factorKilowatt-hourswhat you have× 3.6Megajouleswhat you getBoth units are defined against the same base unit, so the factor is exact — never an approximation.

How to convert kilowatt-hours to megajoules

To convert kilowatt-hours to megajoules, multiply by 3.6. The relationship is fixed, so the same factor works for any quantity — there is nothing to look up and nothing that changes with temperature, location or context.

MJ = kWh × 3.6

Kilowatt-hours to Megajoules conversion table

The values people look up most often, rounded for reading. Use the calculator above for anything in between.

Kilowatt-hoursMegajoules
1 kWh3.6 MJ
2 kWh7.2 MJ
3 kWh10.8 MJ
5 kWh18 MJ
10 kWh36 MJ
20 kWh72 MJ
25 kWh90 MJ
50 kWh180 MJ
100 kWh360 MJ
500 kWh1,800 MJ
1,000 kWh3,600 MJ

What is a kilowatt-hour?

The unit on every electricity bill: a thousand watts for one hour.

What is a megajoule?

A million joules, used for fuel energy content and gas billing.

The formula

MJ = kWh × 3.6

Every result on this page comes from this formula. Nothing is rounded until the final display, so figures match a spreadsheet to the cent.

How to use the Kilowatt-hours to Megajoules

  1. Type the number of kilowatt-hours you want to convert.
  2. Read the result in megajoules straight away — there is no button to press.
  3. Check the table below for the values that come up most often, or reverse the conversion with the linked megajoules to kilowatt-hours page.

Kilowatt-hours to Megajoules — frequently asked questions

How many megajoules are in a kilowatt-hour?

One kilowatt-hour equals 3.6 MJ. MJ = kWh × 3.6

What is the formula to convert kilowatt-hours to megajoules?

The formula is MJ = kWh × 3.6. It is an exact definition rather than an approximation, so the conversion never drifts no matter how large the number.

How do I convert megajoules back to kilowatt-hours?

Divide instead of multiplying: one megajoule is 0.2777777778 kWh. The reverse converter is linked in the related tools list.

Is this conversion exact?

Yes. Both units are defined against the same base unit by international agreement, so the factor is exact — any rounding you see is only in the display, which you can widen by entering more decimal places.

Is this kilowatt-hours to megajoules free to use?

Yes. Every calculator on the site is free, needs no sign-up, and runs entirely in your browser, so your figures never leave your device.

What people search for

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About this calculator

Written and reviewed by The Samsung Calculator editorial team. Every calculator is written against a published formula, reviewed against at least one independent reference implementation, and dated when it changes.

Last reviewed August 19, 2026 · Calculation runs client-side · No data collected · Report an error