Electricity Cost Calculator
Work out how much an appliance costs to run per day, month and year from its wattage, usage and your electricity rate.
From watts to dollars
Electricity is billed in kilowatt-hours (kWh): using 1,000 watts for one hour. Multiply an appliance's wattage by the hours it runs, divide by 1,000, and multiply by your rate.
Cost per day = Watts × Hours ÷ 1,000 × Price per kWh
A 1,500 W space heater used 4 hours a day uses 6 kWh. At 17 cents per kWh that is $1.02 a day, about $31 a month.
Typical appliance wattages
| Appliance | Typical watts |
|---|---|
| LED bulb | 8–12 |
| Laptop | 30–70 |
| Television (LED, 55") | 60–120 |
| Desktop PC with gaming GPU | 300–600 |
| Refrigerator (average running) | 100–200 |
| Microwave | 800–1,200 |
| Space heater / kettle | 1,500–3,000 |
| Central air conditioner | 2,000–4,000 |
| EV charger (level 2) | 7,000–11,000 |
Devices with thermostats or compressors, like fridges and AC units, cycle on and off, so their average draw is lower than the label rating.
Finding your rate
Divide the total on your electricity bill by the kWh used to get your all-in rate, including delivery charges. The US residential average is around 16–17 cents per kWh, but rates range from under 12 cents to over 40 cents depending on the state; European rates are often 25–40 euro cents.
Frequently asked questions
How do I calculate kWh?
Multiply the power in watts by the hours of use and divide by 1,000. A 100 W device used for 10 hours uses 1 kWh.
How much does it cost to run a space heater?
A 1,500 W heater uses 1.5 kWh per hour. At 17 cents per kWh that is about 26 cents an hour.
What uses the most electricity at home?
Heating and cooling usually use the most, followed by water heating, then large appliances such as dryers and refrigerators.
Last reviewed Oct 20, 2026. Results are estimates; check important decisions with a qualified professional.