Household
Watts ↔ kWh
Convert watts to kilowatt-hours for a given usage period
W
h
Result
Energy consumed5 kWh
In watt-hours5000 Wh
How does it work?
Watt (W) is the unit of power — how fast energy is consumed. 1 W = 1 J/s.
Kilowatt-hour (kWh) is the unit of energy — how much energy has been used. 1 kWh = 1000 W × 1 hour = 3,600,000 J.
Formula: kWh = W × hours / 1000. For example, a 500 W appliance running for 4 hours uses 500 × 4 / 1000 = 2 kWh.
kWh is what your electricity bill measures and charges for.
Example
W → kWh: 2000 W washing machine, 1.5 h cycle.
→ 2000 × 1.5 / 1000 = 3.0 kWh
kWh → W: Bill shows 120 kWh/month from fridge running 24/7 ≈ 730 h.
→ 120 × 1000 / 730 = 164 W average
Duration: 5 kWh battery, 300 W load.
→ 5 × 1000 / 300 = 16.7 h
Assumptions
- •Power is constant throughout the time period.