Reference formulas and worked examples below keep their stated units. Monetary examples use USD; dimensional examples use US customary units unless labeled otherwise. Metric calculator inputs are converted to these reference units before calculation. Choosing another currency does not convert example amounts or exchange money.
How to use this electricity cost calculator
Estimate appliance electricity use and cost from watts, hours, days, quantity, and your own price per kWh.
How the calculation works
Energy in kWh = watts × quantity ÷ 1,000 × hours per day × days.
Usage cost = kWh × entered price per kWh. Daily cost divides the period cost by the chosen days.
Worked example
One 1,500 W appliance used four hours daily for 30 days consumes 180 kWh. At $0.16 per kWh, estimated usage cost is $28.80.
Limits and assumptions
Assumes constant average draw and one energy rate. Fixed charges, demand fees, tiered pricing, and time-of-use schedules are excluded.
Frequently asked questions
Can I use this for a heater?
Yes, if you enter its average power and actual operating hours; thermostats can cycle it off.
Where can I find watts?
Check the nameplate, documentation, or a power meter.
Is this my whole electricity bill?
No. It covers the entered appliance usage at the entered energy rate.