Convert watt-hours to megajoules

1 Wh=0.0036MJ

Use the converter below to change any watt-hours value into megajoules instantly — with formula, conversion table, and real-world examples.

You have

Equals

0.0036

Conversion formula

Forward

megajoules = watt-hours × 0.0036

Reverse

watt-hours = megajoules × 277.778

Example: 10 Wh × 0.0036 = 0.036 MJ.

About both units

From

Watt-Hour

The watt-hour equals 3600 joules — 1 W delivered for 1 hour. Used for phone, laptop and small-battery capacities. A typical smartphone battery is 10–20 Wh; a laptop is 50–100 Wh.

Real-world: iPhone battery: 12 Wh. MacBook Pro: 70 Wh. Power bank: 20 Wh–100 Wh. Airplane carry-on limit: usually 100 Wh.

Read full watt-hour reference →

Megajoule

The megajoule equals 1,000,000 joules. Used for fuel energy content, large-scale mechanical work and in some European natural-gas billing. A litre of petrol contains about 34 MJ of energy.

Real-world: 1 L petrol: ~34 MJ. 1 L diesel: ~38 MJ. Tesla Model 3 full charge: ~270 MJ.

Read full megajoule reference →

Watt-Hour to Megajoule conversion table

Common watt-hours to megajoules values for quick reference.

Watt-Hour (Wh)	Megajoule (MJ)
1 Wh	0.0036 MJ
10 Wh	0.036 MJ
100 Wh	0.36 MJ
500 Wh	1.8 MJ
1,000 Wh	3.6 MJ
5,000 Wh	18 MJ
10,000 Wh	36 MJ
50,000 Wh	180 MJ
100,000 Wh	360 MJ
500,000 Wh	1,800 MJ

Tips & common mistakes

Quick tips

1 Wh = 3600 J = 0.001 kWh.
Battery mAh × V = Wh. A 3000 mAh phone battery at 3.7 V = 11.1 Wh.
Airline limits lithium batteries to 100 Wh for carry-on.

Avoid these

Confusing mAh with Wh — need voltage to convert.
Using Wh when kWh is more appropriate for large batteries.
Forgetting the voltage in battery capacity calculations.

Frequently asked questions

How many megajoules in a watt-hour?

One watt-hour equals 0.0036 megajoules.

How do I convert watt-hours to megajoules?

Multiply the watt-hour value by 0.0036 to get the equivalent in megajoules.

What is 100 watt-hours in megajoules?

100 watt-hours equals 0.36 megajoules.

Is a watt-hour bigger than a megajoule?

No. 1 watt-hour equals 0.0036 megajoules, so one watt-hour is smaller.

How to convert watt-hours to megajoules without a calculator?

Multiply by 0 for a quick estimate; use a calculator for precise results.

Related energy conversions

📊 See full comparison matrix →

Conversions in other categories

WeightKilogram → Pound LengthKilometer → Mile TemperatureCelsius → Fahrenheit VolumeLiter → US Gallon AreaSquare Meter → Square Foot SpeedKilometer per Hour → Mile per Hour PressureBar → Pound per Square Inch PowerKilowatt → Mechanical Horsepower