Conversions

Watts to kWh Calculator

Watts measure power; kilowatt-hours measure energy used over time. Enter a wattage and how long it runs to get the energy in kWh and what it costs.

Your details

W
h
$ /kWh

Results

Energy used
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Cost
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Last updated June 30, 2026. Results update automatically as you type.

How it works

Energy (kWh) = watts ÷ 1000 × hours. Cost = energy × rate. For example, a 1,000 W appliance running 3 hours uses 3 kWh.

Frequently asked questions

How many watts in a kWh?

A kWh is 1,000 watts used for one hour — or any equivalent, like 500 W for two hours, or 2,000 W for 30 minutes.

How do I convert watts to kWh per day?

Multiply watts by the hours used per day, then divide by 1,000. A 60 W bulb on for 5 hours uses 0.3 kWh a day.

Why does my bill use kWh not watts?

You pay for total energy consumed over time (kWh), not the instantaneous power draw (watts).

These calculators provide general estimates for educational purposes only and are not financial advice. Real-world results depend on factors not captured here. Verify figures independently before making any purchase or financial decision.

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