Electricity Cost Calculator
Enter your appliance's power rating, how many hours you use it each day, and your electricity rate. The calculator gives you the running cost per day, month, and year.
Electricity Cost Calculator
How it works
The calculation converts watts to kilowatt-hours (kWh), which is the unit electricity companies use to measure and bill your usage.
One kilowatt-hour equals 1,000 watts of power used for one hour. So a 1,000-watt appliance running for 1 hour uses exactly 1 kWh.
Once you have the kWh, multiplying by your electricity rate gives the cost. Rates vary by country and provider — check your electricity bill for the exact figure.
Formula
Divide watts by 1,000 to get kilowatts. Multiply by hours of daily use to get kWh per day. Multiply by days to get monthly or yearly usage. Multiply by your rate to get the cost.
Example: Running a 1,500-watt space heater
A space heater rated at 1,500 watts used for 4 hours a day at an electricity rate of $0.16/kWh.
Result: Daily: $0.96 · Monthly: $28.80 · Yearly: $350.40. The heater uses 6 kWh per day.
Assumptions
- The wattage entered is the appliance's continuous power draw. Some appliances (like refrigerators) cycle on and off, so their actual usage is lower than the rated wattage.
- The rate entered is a flat rate. Many utilities use tiered pricing — your actual bill may differ.
- Monthly cost uses the number of days you specify. Yearly cost assumes the appliance runs every day of the year.
- Taxes and utility fees are not included — add these to your rate if you want a more accurate estimate.