Megajoule to Watt-Hour Converter

Energy Converter

27 units available

Decimals:

From

To

277.777778

1 MJ = 277.777778 Wh

Formula:

Wh = MJ × 277.7777777778

With your value: 1 MJ = 277.77777778 Wh

How big is that?

Everyday references on a logarithmic scale, all expressed in megajoule so you can sanity-check the result.

Heartbeat (1/1.0e+6 your value)0.00000100 MJ

AA battery charge (1/1.0e+2 your value)0.0100 MJ

Slice of bread (1/3.6 your value)0.280 MJ

Your value1.00 MJ

Daily food intake (8.4× your value)8.40 MJ

Litre of petrol (34× your value)34.2 MJ

Other Megajoule to Watt-Hour conversions

2 MJ to Wh 3 MJ to Wh 4 MJ to Wh 5 MJ to Wh 6 MJ to Wh 7 MJ to Wh 8 MJ to Wh

Megajoule to Watt-Hour Conversion Table

Megajoule (MJ)	Watt-Hour (Wh)
0.5	138.888889
1	277.777778
2	555.555556
5	1,388.888889
10	2,777.777778
15	4,166.666667
20	5,555.555556
25	6,944.444444
50	13,888.888889
100	27,777.777778
250	69,444.444444
500	138,888.888889
1000	277,777.777778

Watt-Hour to Megajoule Conversion Table

Watt-Hour (Wh)	Megajoule (MJ)
0.5	0.0018
1	0.0036
2	0.0072
5	0.018
10	0.036
15	0.054
20	0.072
25	0.09
50	0.18
100	0.36
250	0.9
500	1.8
1000	3.6

Where these values come from

Every factor on this page is traced to the document that defines it. See the full provenance dataset or our methodology.

Megajoule (MJ)

Energy

Exact conversion

Derived from the joule (1 J = 1 kg·m²/s²). Thermochemical and IT calories, BTU and kWh are exact defined multiples.

Source: NIST Special Publication 811, Guide for the Use of the International System of Units

National Institute of Standards and Technology (US) · Reviewed 2026-07-01

Watt-Hour (Wh)

Energy

Exact conversion

Derived from the joule (1 J = 1 kg·m²/s²). Thermochemical and IT calories, BTU and kWh are exact defined multiples.

Source: NIST Special Publication 811, Guide for the Use of the International System of Units

National Institute of Standards and Technology (US) · Reviewed 2026-07-01

How to Convert Megajoule to Watt-Hour

To convert from Megajoule (MJ) to Watt-Hour (Wh), multiply the value by 277.7777777778.

Formula: Wh = MJ × 277.7777777778

Reverse: MJ = Wh × 0.0036

Step-by-Step Example

Start with your value in Megajoule. For example: 5 MJ
Multiply by the conversion factor: 5 x 277.7777777778
The result is: 1,388.888889 Wh

About Megajoule

The megajoule (MJ) is a unit of energy and work. One megajoule equals 1.000000 × 10^+6 joules. UnitConvertLab converts it against every other energy unit using this exact definition, so results are reproducible to full double precision rather than rounded lookup tables.

Common uses: energy calculations, engineering and science, education.

About Watt-Hour

The watt-hour (Wh) is a unit of energy and work. One watt-hour equals 3600 joules. UnitConvertLab converts it against every other energy unit using this exact definition, so results are reproducible to full double precision rather than rounded lookup tables.

Common uses: energy calculations, engineering and science, education.

Frequently Asked Questions

How many Watt-Hour are in 1 Megajoule?

There are exactly 277.7777777778 Watt-Hour in 1 Megajoule. This means the conversion factor from Megajoule to Watt-Hour is 277.7777777778.

What is the formula to convert Megajoule to Watt-Hour?

The formula to convert Megajoule to Watt-Hour is: Wh = MJ × 277.7777777778. For example, to convert 10 Megajoule to Watt-Hour, you would multiply 10 by 277.7777777778.

What is a Megajoule?