Electricity Cost Calculator
Enter any appliance’s wattage, how long it runs, and your electricity rate to see the cost per month and year.
WattCost runs every calculation in your browser — your usage and rates never leave this page.Try: Power (watts)=1000, Hours per day=3, Days per month=30, Electricity rate=0.15 → 90.00 kWh, $13.50, $162.00
How to use
Type the device wattage (check the rating label), the hours it runs per day, and your electricity rate. WattCost converts watts to kWh (watts ÷ 1000 × hours × days) and then to a cost using your rate.
Start from any appliance page if you want the typical wattage pre-filled.
FAQ
How do I find an appliance’s wattage?
Look for a rating label on the device or its power supply — it lists watts (W) or amps at a voltage. Multiply amps by volts if only amps are shown.
Why is my bill higher than the estimate?
Estimates use the wattage and hours you enter. Real bills also include fixed charges, taxes, standby loads, and time-of-use rates that a simple calculator does not model.
What does kWh mean?
A kilowatt-hour is 1000 watts run for one hour. It is the unit your utility bills, so cost = kWh × your rate.