Appliance Electricity Bill Calculator
Work out what a single appliance costs to run — per day, per month and per year — from its wattage, hours of use and your electricity rate.
How it works
kWh/day = (watts ÷ 1000) × hours · Cost = kWh × rate per kWh
Energy in kilowatt-hours is the appliance’s power in kilowatts multiplied by the hours it runs, and the bill is that energy times your per-kWh rate. A device’s nameplate watts is its maximum draw; motors and heaters cycle on and off, so their average consumption is often lower than continuous running. For always-on gadgets, remember standby power still counts — a few watts around the clock adds up over a year.
Worked example
A 1,500 W space heater run 3 hours a day uses (1500 ÷ 1000) × 3 = 4.5 kWh per day. At $0.17/kWh that is $0.765 a day, roughly $22.95 a month or $279 a year.
Frequently asked questions
Where do I find an appliance’s wattage?
Check the label on the back or bottom, or the manual. If only amps and volts are listed, multiply them (watts = volts × amps) — a 120 V, 10 A device draws about 1,200 W.
What electricity rate should I enter?
Use the per-kWh rate on your utility bill. US residential rates commonly fall between $0.12 and $0.30 per kWh depending on region; include delivery charges for the truest figure.
Does this account for standby power?
Only if you include those hours. Many electronics draw 1–5 watts even when off; to capture that, run a separate calculation at the standby wattage for 24 hours a day.
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This calculator is for educational purposes. Double-check important results before acting on them.