A kilowatt-hour is 3.6 million joules.
kWhs to Watt-hours Converter — kWh to Wh
Convert kWh (kWh) to Watt-hour (Wh) using the exact conversion factor (1 kwh = 1,000 watt-hour). See the formula, worked examples, conversion table, unit comparison, history, and common uses.
kWhs to Watt-hours converter
Converter
Energy Converter
Convert joules, calories, kilowatt-hours, BTU, electronvolts, therms, and mechanical work units.
Context values
Some unit families need one extra value for a physically accurate result.
A watt-hour is 3,600 joules.
Result = input x 3.6e+6 / 3600.
Energy uses the joule as the base unit.
Reserved above the conversion cards and below the converter.
About Converting kWhs to Watt-hours
kWh and Watt-hour both measure energy, and the conversion is especially useful for comparing nutrition labels (kilocalories) against scientific energy figures (joules). kWh is typically associated with used worldwide for electricity billing, while Watt-hour is typically associated with universal — standard consumer-electronics and battery energy unit worldwide.
Formula
watt-hours = kwhs × 1000
This factor comes from each unit's defined relationship to the category's base unit: 1 kwh equals 3600000 base units, and 1 watt-hour equals 3600 base units, so dividing one by the other gives the direct kwh-to-watt-hour factor of 1000.
Simple example
1 kWh × 1000 = 1,000 Wh
1 kwh = 1,000 watt-hours.
Real-world example
100 kWh × 1000 = 100,000 Wh
100 kwhs = 100,000 watt-hours.
Conversion table
| kWh (kWh) | Watt-hour (Wh) |
|---|---|
| 1 kWh | 1,000 Wh |
| 10 kWh | 10,000 Wh |
| 100 kWh | 100,000 Wh |
| 500 kWh | 500,000 Wh |
| 1,000 kWh | 1,000,000 Wh |
| 2,000 kWh | 2,000,000 Wh |
Reverse conversion: Watt-hour to kWh
1 Wh × 0.001 = 0.001 kWh
1 watt-hour = 0.001 kwhs.
kwhs = watt-hours × 0.001
For a page dedicated to this direction, see Watt-hour to kWh.
kWh vs. Watt-hour
| Aspect | kWh | Watt-hour |
|---|---|---|
| Family | Non-SI unit accepted for use with SI | metric derived energy unit |
| Typical use | Residential and commercial electricity billing worldwide | Phone, laptop, and power-bank battery capacity ratings |
| Where it's used | Used worldwide for electricity billing | Universal — standard consumer-electronics and battery energy unit worldwide |
Understanding the kWh
kWh (kWh) measures energy. A kilowatt-hour is the energy of one kilowatt of power sustained for one hour: exactly 3,600,000 joules. It is classified as a Non-SI unit accepted for use with SI.
Where it's used: Used worldwide for electricity billing
Uses of the kWh today
- Residential and commercial electricity billing worldwide
- Battery capacity ratings (especially electric vehicles)
- Energy policy and grid-scale power statistics
History of the kWh
The kilowatt-hour became the standard electricity billing unit as power utilities expanded in the late 19th and early 20th centuries, since it conveniently matches the scale of typical household electricity consumption, unlike the much smaller joule.
Historical origin. kWh was not the invention of a single named person; it developed through the process described above.
Understanding the Watt-hour
Watt-hour (Wh) measures energy. The energy delivered by one watt of power sustained for one hour — equal to 3,600 joules. It is classified as a metric derived energy unit.
Where it's used: Universal — standard consumer-electronics and battery energy unit worldwide
Wh vs. kWh. The same unit at different scales: 1,000 Wh equals 1 kWh. Wh suits small consumer-electronics batteries; kWh is used for household electricity billing and larger energy storage.
Uses of the Watt-hour today
- Phone, laptop, and power-bank battery capacity ratings
- Electric-vehicle battery capacity specifications
- Small-scale renewable energy (solar panel) output ratings
kWh — sources
- BIPM SI Brochure — Non-SI units accepted for use with SI — Lists the kilowatt-hour among accepted non-SI energy units.
Watt-hour — sources
- BIPM SI Brochure — Watt-hour as a common energy unit derived from the coherent SI units watt and second (via the hour).
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many watt-hours are in 1 kwh?
1 kwh equals 1,000 watt-hours, using the exact defined conversion factor rather than an estimate.
How do I convert kwh to watt-hour?
Multiply the kwh value by 1000. The converter above does this instantly to whatever precision you set.
How do I convert watt-hour back to kwh?
Use the reverse factor: 1 watt-hour equals 0.001 kwhs. You can also use the swap control in the converter above to flip the direction instantly.
What is a kwh?
kWh (kWh) measures energy. A kilowatt-hour is the energy of one kilowatt of power sustained for one hour: exactly 3,600,000 joules. It is classified as a Non-SI unit accepted for use with SI.
What is a watt-hour?
Watt-hour (Wh) measures energy. The energy delivered by one watt of power sustained for one hour — equal to 3,600 joules. It is classified as a metric derived energy unit.
Is the kwh to watt-hour conversion exact?
Yes. A kilowatt-hour is the energy of one kilowatt of power sustained for one hour: exactly 3,600,000 joules. That fixed definition is what the converter above uses, so any rounding you see is a display choice, not a limitation of the math.
What is the difference between wh vs. kwh?
The same unit at different scales: 1,000 Wh equals 1 kWh. Wh suits small consumer-electronics batteries; kWh is used for household electricity billing and larger energy storage.
Where is the kwh still used today?
Used worldwide for electricity billing