Formula
P (kW) = E (kWh) ÷ t (hours)
This gives the average power over the period — actual demand fluctuates moment to moment.
Worked example
An air conditioner that used 10 kWh over a 5-hour evening averaged P = 10 ÷ 5 = 2 kW of power draw.
Reference table
10 kWh spread over different durations
| Hours | Average kW for 10 kWh |
|---|---|
| 0.5 | 20 |
| 1 | 10 |
| 2 | 5 |
| 4 | 2.5 |
| 8 | 1.25 |
| 24 | 0.42 |
Where this shows up in the real world
Utility bills, EV dashboards and solar apps all speak kWh; equipment and wiring speak kW. Converting between them answers practical money questions: if the bill shows 30 kWh/day, what's the average kW draw (1.25 kW), and could a 5 kW solar array realistically cover it? US average household use runs near 29 kWh a day — useful context for any audit.
Common mistakes to avoid
The eternal confusion is treating kW and kWh as interchangeable — one is speed, the other is distance. A 3 kW load for 2 hours and a 1 kW load for 6 hours are the same 6 kWh on the bill but very different wiring problems. Also remember the result is an *average*: peak demand, which some commercial tariffs bill separately, can be several times higher.
Frequently asked questions
Are kWh and kW the same thing?
No. kW is power (the rate of using energy); kWh is energy (power sustained over time). A 2 kW heater running 3 hours uses 6 kWh.
Why does my bill show kWh?
Utilities charge for energy consumed. 'Units' on bills in Pakistan, India and many other countries are simply kWh.
Can I go the other way?
Yes: kWh = kW × hours. A 1.5 kW appliance running 4 hours daily uses 6 kWh per day, about 180 units a month.