Electricity Cost Calculator

April 6, 2026 · Free Online Tool

Electricity Cost Calculator

Enter your values below and click Calculate

Device Wattage (W)

Hours Used Per Day

Days Per Month

Electricity Rate ($/kWh)

Your Result

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Formula: watts * hours * days / 1000 * rate

Calculate How Much an Appliance Costs to Run

Find out the monthly electricity cost of any appliance or device. Enter its wattage, daily usage, and your electricity rate.

Common Appliance Wattages

Space heater: 1,500W ($46.80/month at 8hrs/day)
Window AC: 900W ($28.08/month at 8hrs/day)
LED light bulb: 10W ($0.31/month at 8hrs/day)
Gaming PC: 500W ($15.60/month at 8hrs/day)
Refrigerator: 150W ($14.04/month, runs 24hrs)

Formula

Monthly cost = (Watts x Hours/day x Days) / 1,000 x Rate per kWh. The average US electricity rate is $0.13/kWh but varies by state from $0.08 (Idaho) to $0.28 (Hawaii).