Everyday
Electricity cost calculator
Enter an appliance's wattage, how many hours per day it runs, and your electricity rate ($/kWh). The calculator returns energy use (kWh) and cost ($) for a day, month, and year.
Formula
Watts × hours ÷ 1000 = kilowatt-hours (kWh), the unit your electric bill is measured in. Multiply by your rate to get cost. Most US households pay $0.10-0.20 per kWh; UK ~£0.25; Germany €0.30+ (some of the world's highest).
Wattage is printed on the device label or in the manual. Typical figures: LED bulb 8 W, gaming PC 300-500 W, fridge ~150 W (cycles on/off, avg ~50 W), AC unit 1000-2000 W, electric kettle 1500 W, oven 2000-3000 W, electric heater 1500 W, microwave 1100 W.
For devices with variable power (TVs, computers), check the wattage rating or use a kill-a-watt meter. Standby power (devices plugged in but 'off') can add 5-10% to a home's total bill.
Examples
- 01100 W lamp, 8 h/day, $0.15/kWh→ 0.8 kWh/day · $0.12/day · $43.80/year
- 02Gaming PC 400 W, 4 h/day, $0.20/kWh→ 1.6 kWh/day · $0.32/day · $116.80/year
- 03AC 1500 W, 6 h/day in summer (90 days), $0.15/kWh→ 9 kWh/day × 90 = 810 kWh · $121.50 for the summer
- 04Fridge 150 W average, 24 h/day, $0.15/kWh→ 3.6 kWh/day · $0.54/day · $197.10/year (always-on)
FAQ
- On your bill — look for '$/kWh' or 'per kWh'. Time-of-use plans have different rates by hour. For an average, divide total bill by total kWh used.
References
Note: Results are accurate to floating-point precision (~15 significant digits) for the standard formula shown above. See our terms of use for general usage information.