Electricity Cost Calculator
Calculate the estimated cost of running any household appliance based on its wattage and your local energy rates.
Runs in your browser Your input never leaves your device.
About this tool
Enter an appliance's power in watts, how many hours a day it runs, the number of days and the price you pay per kilowatt-hour. The tool converts watts to kilowatts, then multiplies by hours and days to get energy in kWh: watts / 1000 x hours x days. The cost is that energy times your rate. Days start at 30, so by default you get roughly a month. Cost has no currency symbol, so it is shown in whatever currency your rate uses. The result is an estimate that assumes the device draws its rated power the whole time, which many devices do not. Everything is calculated in your browser.
How to use it
- Enter the device power in watts, from its label.
- Enter how many hours per day it runs.
- Set the number of days (30 by default).
- Enter your cost per kWh and read the energy and cost.
Example
0.150 kW x 8 h x 30 days = 36 kWh; 36 x 0.15 = 5.40.
150 W, 8 hours per day, 30 days, rate 0.15
Energy used: 36 kWh Cost: 5.40
Common problems
- The estimate is higher than my bill
- Rated watts are often a maximum. Fridges, heaters and many electronics cycle on and off, so average draw can be much lower.
- No result is shown
- Power must be greater than zero.
- I entered the rate in cents
- Use the same unit throughout. If your rate is 15 cents per kWh, enter 0.15 to get dollars, or 15 to get cents.