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Electricity Cost Calculator
See what any appliance costs to run from its wattage, daily use and your electricity rate.
Enter the appliance's watts, hours of use and your rate.
Formula
kWh = watts ÷ 1,000 × hours per day × days · Cost = kWh × rate ($ per kWh)
How to calculate
- 1Divide the appliance's wattage by 1,000 to get kilowatts.
- 2Multiply by the hours it runs per day to get daily kilowatt-hours.
- 3Multiply by your electricity rate for the daily cost.
- 4Multiply the daily cost by 30 for a monthly estimate.
How to use this calculator
- 1Enter the appliance's wattage (check its label).
- 2Enter how many hours a day it typically runs.
- 3Enter your electricity rate per kWh from your bill.
- 4See the running cost per day, month and year.
Examples
Space heater
1,500 W for 6 h/day at $0.15/kWh → 9 kWh, $1.35/day — around $40 in a month.
Light bulb
A 60 W bulb for 5 h/day at $0.15/kWh → 0.3 kWh, $0.045/day — under $1.50 a month.
Common questions
Where do I find my electricity rate?
On your utility bill, quoted as cents or dollars per kWh. The US average sits around $0.15–0.17 per kWh.
Do standby devices really cost money?
A few watts each, around the clock — small per device, but across a whole household it becomes visible on a yearly bill.
Is this an exact bill?
No — it is an estimate. Real bills include tiered rates, taxes and fixed fees that this calculation leaves out.
