Enter an appliance’s wattage, how long you use it and your electricity rate to see its energy use and running cost per day, month and year.
How to use the electricity cost calculator
Enter the appliance's power rating in watts, the number of identical devices, how many hours a day it runs, how many days a week, and your electricity price per kilowatt-hour (kWh). The calculator shows the energy used and the running cost per hour, per day of use, per week, per month and per year. Use it to price a space heater, air conditioner, gaming PC, aquarium heater, EV charger, crypto miner or any other device.
The power rating is printed on a label on the appliance, its power brick or in the manual. If only amps and volts are given, multiply them: a 10 A device on a 230 V supply draws about 2,300 W. For the most accurate figure, measure actual consumption with a plug-in energy monitor, because many appliances do not run at full power all the time.
The electricity cost formula
A kilowatt-hour is the energy used by a 1,000-watt device running for one hour — the unit your utility bills you in. Monthly cost here is the yearly figure divided by 12, so it reflects an average month.
Worked example
A 1,500 W space heater runs 4 hours a day, every day, at 0.17 per kWh:
- 1,500 W ÷ 1,000 = 1.5 kW.
- 1.5 kW × 4 h = 6 kWh per day, costing 6 × 0.17 = 1.02.
- Per year: 6 × 365 = 2,190 kWh × 0.17 = 372.30, or about 31.03 a month.
Each hour of heating costs 0.255. Cutting use to 3 hours a day would save about 93 a year.
Typical appliance wattages
| Appliance | Typical power |
|---|---|
| LED light bulb | 5–15 W |
| Wi-Fi router | 5–20 W |
| Laptop | 30–90 W |
| LED TV (55") | 60–150 W |
| Refrigerator (average while cycling) | 100–250 W |
| Gaming PC under load | 300–700 W |
| Microwave | 800–1,200 W |
| Space heater / kettle | 1,500–3,000 W |
| Window / split AC | 800–2,500 W |
| Level 2 EV charger | 7,000–11,000 W |
Devices with thermostats or compressors — fridges, freezers, air conditioners, water heaters — cycle on and off, so their average draw is well below their rated power. Enter the hours they actually run, or use the average wattage.
Electricity prices around the world
Residential electricity prices differ enormously. In 2025–26, typical household rates were around 0.15–0.20 USD per kWh in the United States (much higher in California and Hawaii), about 0.26 GBP per kWh under the UK price cap (26.32p for October–December 2026, plus a daily standing charge), often 0.25–0.40 EUR in Germany and other parts of Western Europe, and roughly 5–8 INR in India, depending on the state and slab. Many utilities also charge time-of-use rates that are cheaper at night, plus a fixed daily standing charge that does not depend on usage. Check your latest bill for your exact rate and enter it above.
Results are estimates; actual costs depend on real usage, tariffs, taxes and fixed charges.
Cite or link to this page
Using this electricity cost calculator in an article, report or homework? Copy a citation or a ready-made link:
Calcivia. (2026). Electricity Cost Calculator. Retrieved October 31, 2026, from https://www.calcivia.com/electricity-cost-calculator/"Electricity Cost Calculator." Calcivia, 2026, https://www.calcivia.com/electricity-cost-calculator/. Accessed 31 Oct. 2026.<a href="https://www.calcivia.com/electricity-cost-calculator/">Electricity Cost Calculator</a> by Calcivia