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Kilowatt-hours to watt-hours

Multiply kilowatt-hours by 1,000 to get watt-hours.

1 kWh = 1,000 WhNIST SP 811
kWh
5,000Wh

5 kWh = 5,000 Wh

How to convert kilowatt-hours to watt-hours

The watt-hour is one watt sustained for one hour, exactly 3600 joules — one thousandth of a kilowatt-hour. The kilowatt-hour is one kilowatt for one hour, exactly 3.6 megajoules — the electricity billing unit.

Worked example — 5 kWh: 5 × 1,000 = 5,000 Wh.

Kilowatt-hours to watt-hours table

Common conversions. The reverse table is on watt-hours to kilowatt-hours.
Kilowatt-hoursWatt-hours
0.1 kWh100 Wh
0.5 kWh500 Wh
1 kWh1,000 Wh
2 kWh2,000 Wh
5 kWh5,000 Wh
10 kWh10,000 Wh
13.5 kWh13,500 Wh
50 kWh50,000 Wh
75 kWh75,000 Wh

Reverse and related

About kilowatt-hours and watt-hours

Kilowatt-hour (kWh)

1 kWh = 1,000 Wh

Definition. One kilowatt for one hour, exactly 3.6 megajoules — the electricity billing unit

History and origin

The kilowatt-hour is the energy of one kilowatt sustained for one hour, exactly 3.6 megajoules. It became the standard way to bill electricity as power grids spread.

Current use

Kilowatt-hours are the unit on electricity bills and describe the capacity of batteries, including electric-vehicle packs.

Source: NIST SP 811, Appendix B; ISO 80000-5 (energy)

Watt-hour (Wh)

1 Wh = 0.001 kWh

Definition. One watt sustained for one hour, exactly 3600 joules — one thousandth of a kilowatt-hour

History and origin

The watt-hour is the energy of one watt delivered for one hour, exactly 3600 joules. It is one thousandth of the kilowatt-hour used on electricity bills.

Current use

Watt-hours rate battery capacity — phone, laptop and power-bank batteries are labelled in Wh or mWh.

Source: NIST SP 811, Appendix B; ISO 80000-5 (energy)

Where people use this

Kilowatt-hours: electricity bills, EV batteries. Watt-hours: battery capacity, small appliances. A 13.5 kWh home battery is 13,500 Wh.

How we know this is right
The factor is fixed by the standards that define the units, not chosen — so it is exact, not a measurement:
1 Wh = 0.001 kWh, so 1 kWh = 1 ÷ 0.001 = 1,000 Wh.

Every value is carried to full double precision; the display is rounded.

Both units are defined in NIST SP 811, Appendix B; ISO 80000-5 (energy).

Questions people ask

How many Wh is 1 kWh?

One kilowatt-hour is 1000 watt-hours.

How many Wh is 13.5 kWh?

A 13.5 kWh home battery is 13,500 Wh.

How many Wh is 0.5 kWh?

Half a kWh is 500 Wh.

All kilowatt-hour conversions