What is the formula for converting kW to kWh?

The formula is kWh = kW × hours. Power (kW) multiplied by time (h) gives energy (kWh). For example, a 2 kW heater running for 3 hours consumes 2 × 3 = 6 kWh.

What is the difference between kW and kWh?

kW (kilowatts) is a measure of power — the rate at which energy is used at any instant, like speed. kWh (kilowatt-hours) is a measure of energy — the total electricity consumed over time, like distance. kWh = kW × hours.

How do I convert minutes or seconds to hours for this calculator?

Divide minutes by 60 to get hours (e.g., 90 minutes = 1.5 h). Divide seconds by 3600 to get hours (e.g., 1800 seconds = 0.5 h). Enter the decimal hours value in the Time field.

How much does 1 kWh of electricity cost?

The cost varies by location and tariff. In the United States the average residential rate is roughly $0.12–$0.18 per kWh. Multiply your kWh result by your local rate to estimate the electricity cost.

Can I convert watts to kWh with this tool?

Divide your wattage by 1000 to get kilowatts first (e.g., 500 W = 0.5 kW), then enter that value in the Power field. The rest of the calculation is the same.

A 1.5 kW appliance runs for 4 hours — how many kWh is that?

kWh = 1.5 kW × 4 h = 6 kWh. At $0.15 per kWh that would cost $0.90.

Kilowatts to Kilowatt Hours Calculator

Name: Kilowatts to Kilowatt Hours Calculator
Availability: InStock
Author: Nham Vu

Enter power in kilowatts (kW) and duration in hours to instantly calculate energy consumption in kilowatt-hours (kWh).

Input Values

Power (kW)

Time (hours) e.g. 1.5 for 90 min

Result

Enter values and press Calculate

Formula

Energy Formula

kWh = kW × hours

Example

2.5 kW × 4 h = 10 kWh

Result copied!

Summary

Enter power in kilowatts (kW) and duration in hours to instantly calculate energy consumption in kilowatt-hours (kWh).

How it works

Enter the power of the device or load in kilowatts (kW).
Enter the duration the device runs in hours (h).
Press Calculate to see the energy result in kilowatt-hours (kWh).
The breakdown panel shows the applied formula and intermediate values.
Use the Copy Result button to copy the kWh value to your clipboard.
Press Reset to clear all fields and start a new calculation.

Use cases

Estimate how many kWh an appliance uses over a day, week, or month.
Calculate the energy cost of running a heater, air conditioner, or EV charger.
Size a solar panel or battery bank to cover a known kW load for a set number of hours.
Convert a generator or motor power rating to expected energy output over a shift.
Verify electricity bill charges by comparing metered kWh to expected kWh.
Plan industrial equipment energy budgets for a production run.
Determine charging energy for an EV given the charger power and session length.
Cross-check energy consumption estimates in building energy audits.

Frequently Asked Questions

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Last updated: 2026-05-23 · Reviewed by Nham Vu