Watt Hours to Kilowatt Hours
An instant watt hours-to-kilowatt hours converter, with the formula and a reference table below.
| Watt Hours | Kilowatt Hours |
|---|---|
| 1 Wh | 0.001 kWh |
| 2 Wh | 0.002 kWh |
| 3 Wh | 0.003 kWh |
| 5 Wh | 0.005 kWh |
| 10 Wh | 0.01 kWh |
| 25 Wh | 0.025 kWh |
| 50 Wh | 0.05 kWh |
| 100 Wh | 0.1 kWh |
How to use
- Enter a value in the Watt Hours field.
- The Kilowatt Hours figure appears immediately — no button to press.
- Typing in the Kilowatt Hours field converts back to Watt Hours the same way.
- Use the reference table for the values that come up most often.
Watt Hours to Kilowatt Hours formula
Converting watt hours to kilowatt hours is a single multiplication by 0.001.
kWh = Wh × 0.001
Put another way, one watt-hour is exactly 1/1,000 of a kilowatt-hour.
Why this factor: the watt-hour and the kilowatt-hour are both defined against the joule, so dividing one definition by the other gives 0.001 directly. Both definitions are set out in full below.
To go the other way, divide by 0.001 — or use the Kilowatt Hours to Watt Hours converter, which is the same calculation reversed.
Worked example
Take 500 Wh and multiply by the factor 0.001: the result is 0.5 kWh.
500 Wh × 0.001 = 0.5 kWh
The converter above does this for any value you type, in either direction.
What is a watt-hour?
A watt-hour is the energy delivered by one watt of power sustained for one hour.
Definition: Exactly 3,600 joules.
Where it is used: Battery capacity for laptops, e-bikes and power tools, and small-scale energy metering.
Worth knowing: Airline lithium-battery limits are set in watt-hours, which is why laptop and power-bank capacities are labelled in Wh.
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.
Watt Hours vs Kilowatt Hours
The watt-hour and the kilowatt-hour belong to the same family of units, so converting between them is usually a matter of shifting a decimal point or applying a small whole-number factor.
Frequently asked questions
How many kilowatt hours are in a watt-hour?
One watt-hour equals 0.001 kilowatt hours.
What is the formula to convert watt hours to kilowatt hours?
Multiply the number of watt hours by 0.001. To reverse it, divide by 0.001 instead.
How do I convert kilowatt hours back to watt hours?
Divide by 0.001, which is the same as multiplying by 1000.
How many kilowatt hours are in 10 watt hours?
10 Wh works out to 0.01 kWh.
Is there anything to watch out for with watt hours?
Airline lithium-battery limits are set in watt-hours, which is why laptop and power-bank capacities are labelled in Wh.
How is the watt-hour defined?
Exactly 3,600 joules.