Kilowatts to Kilowatt-Hours Calculator
Convert power in kilowatts (kW) to energy in kilowatt-hours (kWh). Enter the power in kilowatts and the consumption time period in hours, and press Calculate to get the energy in kWh. Everything runs locally in your browser.
Enter the power in kilowatts
Type the average power consumption of your device in kW. Appliance nameplates usually list watts — divide by 1000 first (1500 W = 1.5 kW). Scientific notation like 2.5e-3 works too.
Enter the time in hours
Type how long the device runs, in hours. Fractional hours are fine: 30 minutes is 0.5 h, 15 minutes is 0.25 h, and a full day is 24 h.
Press Calculate, read kWh
The energy in kilowatt-hours appears at once (at most 4 decimal places). Copy the result to your clipboard, or press Reset to start over.
How kilowatts become kilowatt-hours
- What is the kW to kWh formula?
- The energy E in kilowatt-hours (kWh) is equal to the power P in kilowatts (kW), times the time period t in hours (h): E(kWh) = P(kW) × t(h). Power is a rate; energy is that rate sustained over time.
- How do you convert 5 kW to kWh?
- Multiply the power by the running time. A 5 kW load running for 2 hours consumes 5 × 2 = 10 kWh. For the same 5 kW running only 30 minutes (0.5 h), it is 5 × 0.5 = 2.5 kWh.
- How much energy does a 0.5 kW device use in a day?
- Left running around the clock, 0.5 kW × 24 h = 12 kWh per day. The same energy equals a 1.5 kW device running for 8 hours (1.5 × 8 = 12 kWh) — different power, same total energy.
- What is the difference between kW and kWh?
- A kilowatt (kW) measures power — how fast energy is used at an instant. A kilowatt-hour (kWh) measures energy — power multiplied by elapsed time. It is the distance-vs-speed analogy: kWh is the distance driven, kW is the speed.
- How do I turn kWh into a cost?
- Multiply the kWh result by your electricity tariff. For example, 12 kWh at $0.15 per kWh costs 12 × 0.15 = $1.80. Utilities bill in kWh, so this calculator gives you the quantity they charge for.
Privacy: every calculation runs in your browser tab — no value you type is sent anywhere. The copy button uses your clipboard only. Real devices vary their draw over time; use average power for realistic energy estimates.