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Energy

Convert watt-hours to kilojoules

1 Wh=3.6kJ

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

3.6

Conversion formula

Forward
kilojoules = watt-hours × 3.6
Reverse
watt-hours = kilojoules × 0.2778

Example: 10 Wh × 3.6 = 36 kJ.

About both units

From

Watt-Hour

Wh

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 →
To

Kilojoule

kJ

The kilojoule equals 1000 joules. Used on European nutrition labels (required by EU law alongside kcal), for mechanical work specifications, and some engineering contexts. A 100 g chocolate bar contains about 2100 kJ.

Real-world: 100 g chocolate: ~2100 kJ. EU daily intake (adult): ~8400 kJ. Tesla Model 3 battery: ~270 MJ = 270,000 kJ.
Read full kilojoule reference →

Watt-Hour to Kilojoule conversion table

Common watt-hours to kilojoules values for quick reference.

Watt-Hour (Wh)Kilojoule (kJ)
1 Wh3.6 kJ
10 Wh36 kJ
100 Wh360 kJ
500 Wh1,800 kJ
1,000 Wh3,600 kJ
5,000 Wh18,000 kJ
10,000 Wh36,000 kJ
50,000 Wh180,000 kJ
100,000 Wh360,000 kJ
500,000 Wh1,800,000 kJ

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 kilojoules in a watt-hour?
One watt-hour equals 3.6 kilojoules.
How do I convert watt-hours to kilojoules?
Multiply the watt-hour value by 3.6 to get the equivalent in kilojoules.
What is 100 watt-hours in kilojoules?
100 watt-hours equals 360 kilojoules.
Is a watt-hour bigger than a kilojoule?
Yes. 1 watt-hour equals 3.6 kilojoules, so one watt-hour is larger.
How to convert watt-hours to kilojoules without a calculator?
Multiply by 3.6 for a quick estimate; use a calculator for precise results.

Related energy conversions

📊 See full comparison matrix →

More from Watt-Hour

Wh → J
1 = 3,600 J
Wh → MJ
1 = 0.0036 MJ
Wh → kWh
1 = 0.001 kWh
Wh → cal
1 = 860.421 cal
Wh → kcal
1 = 0.8604 kcal
Wh → BTU
1 = 3.41214 BTU
Wh → eV
1 = 2.2469e22 eV
Wh → thm
1 = 3.4121e-5 thm

More to Kilojoule

J → kJ
1 = 0.001 kJ
MJ → kJ
1 = 1,000 kJ
kWh → kJ
1 = 3,600 kJ
cal → kJ
1 = 0.004184 kJ
kcal → kJ
1 = 4.184 kJ
BTU → kJ
1 = 1.05506 kJ
eV → kJ
1 = 1.6022e-22 kJ
thm → kJ
1 = 105,505.59 kJ

Conversions in other categories

WeightKilogram → PoundLengthKilometer → MileTemperatureCelsius → FahrenheitVolumeLiter → US GallonAreaSquare Meter → Square FootSpeedKilometer per Hour → Mile per HourPressureBar → Pound per Square InchPowerKilowatt → Mechanical Horsepower