Megajoules to Kilowatt Hours
Type a value in either box to convert between megajoules and kilowatt hours. The factor is 0.277778.
| Megajoules | Kilowatt Hours |
|---|---|
| 1 MJ | 0.277778 kWh |
| 2 MJ | 0.555556 kWh |
| 3 MJ | 0.833333 kWh |
| 5 MJ | 1.388889 kWh |
| 10 MJ | 2.777778 kWh |
| 25 MJ | 6.944444 kWh |
| 50 MJ | 13.888889 kWh |
| 100 MJ | 27.777778 kWh |
How to use
- Enter a value in the Megajoules field.
- The Kilowatt Hours figure appears immediately — no button to press.
- Typing in the Kilowatt Hours field converts back to Megajoules the same way.
- Use the reference table for the values that come up most often.
Megajoules to Kilowatt Hours formula
The factor from megajoules to kilowatt hours is 0.277777778.
kWh = MJ × 0.277777778
Put another way, one megajoule is exactly 5/18 kilowatt hours.
Why this factor: the megajoule and the kilowatt-hour are both defined against the joule, so dividing one definition by the other gives 0.277777778 directly. Both definitions are set out in full below.
To go the other way, divide by 0.277777778 — or use the Kilowatt Hours to Megajoules converter, which is the same calculation reversed.
Worked example
Given 500 MJ, multiplying by 0.277777778 yields 138.888889 kWh.
500 MJ × 0.277777778 = 138.888889 kWh
The converter above does this for any value you type, in either direction.
What is a megajoule?
A megajoule is one million joules, used for substantial energy quantities.
Definition: Exactly 1×10⁶ joules. One kilowatt-hour is exactly 3.6 MJ.
Where it is used: Fuel energy content, natural gas billing, and industrial energy accounting.
What is a kilowatt-hour?
A kilowatt-hour is the standard billing unit for electricity — one kilowatt drawn for one hour.
Definition: Exactly 3.6 megajoules.
Where it is used: Electricity bills worldwide, solar generation figures, and electric vehicle battery capacity.
Megajoules vs Kilowatt Hours
The megajoule is a metric unit while the kilowatt-hour is a specialized unit. That is why the factor between them is not a round number: the two systems were defined independently and only later tied together by exact agreement.
Frequently asked questions
How many kilowatt hours are in a megajoule?
One megajoule equals 0.277777778 kilowatt hours.
What is the formula to convert megajoules to kilowatt hours?
Multiply the number of megajoules by 0.277777778. To reverse it, divide by 0.277777778 instead.
How do I convert kilowatt hours back to megajoules?
Divide by 0.277777778, which is the same as multiplying by 3.6.
How many kilowatt hours are in 10 megajoules?
10 MJ works out to 2.777778 kWh.
How is the megajoule defined?
Exactly 1×10⁶ joules. One kilowatt-hour is exactly 3.6 MJ.