This electricity cost calculator shows how much any appliance costs to run per hour, day, month and year. Enter its power in watts, how long you use it and your electricity price per kilowatt-hour, in any currency.
How to calculate electricity cost
kWh per day = watts × hours used ÷ 1,000
Cost = kWh × price per kWh
A kilowatt-hour (kWh) is the unit on your electricity bill: 1,000 watts used for one hour.
Worked example
A 1,500 W space heater used 4 hours a day uses 6 kWh a day. At $0.17 per kWh, that is $1.02 a day, about $31 a month and $372 a year if used every day.
Typical appliance power
| Appliance | Typical power |
|---|---|
| LED bulb | 8–12 W |
| Laptop | 30–70 W |
| TV (LED, 50 inch) | 60–120 W |
| Refrigerator | 100–250 W while running |
| Microwave | 800–1,200 W |
| Space heater | 750–1,500 W |
| Electric kettle | 1,500–3,000 W |
| Clothes dryer | 2,000–5,000 W |
These are rough ranges; check the label on your appliance or its manual for the exact rating.
Finding your electricity price
Your bill shows your price per kWh. If it lists several charges, divide the total energy charges by the kWh used to get an average. Time-of-use plans charge different prices at different times, so use the price for when the appliance runs.
Frequently asked questions
How do I find how many watts an appliance uses?
Look for a label on the back or bottom of the appliance, or in its manual. If it shows amps and volts instead, multiply them to get watts.
Why is my bill higher than this estimate?
Bills include fixed daily charges, taxes and every other device in the home. Appliances such as heaters may also run for longer than you think.
Do appliances use electricity when switched off?
Many use a small amount on standby, often 1–5 W each. Across a home this can add up; a smart plug or power strip can cut it.
What is the difference between kW and kWh?
kW is power, the rate of using electricity. kWh is energy, the amount used over time. A 1 kW appliance running for 2 hours uses 2 kWh.
How much does it cost to charge an electric car?
Use the EV charging cost calculator, which works from battery size and charging losses.
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Sources
Last reviewed: October 2026.