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Appliance energy cost calculator
Find out how many kWh an appliance uses and what it costs to run per day, month and year from its watts, daily hours and your electricity rate.
Results
| Cost per year | $78.84 |
|---|---|
| Cost per month | $6.57 |
| Cost per day | $0.216 |
| Energy per day | 1.2 kWh |
| Energy per year | 438 kWh |
- A plug-in energy meter measures real consumption over a week. It's the most accurate input for fridges, dehumidifiers and anything with a thermostat.
About this calculator
Utility bills show what the whole house used. They don't show what the space heater, the old garage fridge or the gaming PC costs on its own. Working it out is simple once you know the appliance's power draw and how long it runs: watts × hours gives watt-hours, and the utility charges per thousand of them (kWh).
This calculator turns any appliance's watts and daily hours into energy use and cost per day, month and year at your actual rate, including standby power that many devices draw while "off".
How to use it
- Enter the appliance's watts from the label, or better, from a plug-in meter.
- Enter typical hours of use per day. A fridge that cycles runs 24 h at its average watts.
- Enter your all-in electricity price from your bill.
- Optionally add standby watts to see the cost of devices left plugged in.
The formula
kWh per day = (watts × hours on + standby watts × hours off) ÷ 1000.
Cost = kWh × price per kWh. Monthly = yearly ÷ 12.
Worked example (default values)
Inputs
| Appliance power | 150 W |
|---|---|
| Hours used per day | 8 h/day |
| Electricity price | 0.18 $/kWh |
| Standby draw when off | 0 W |
Results
| Cost per year | $78.84 |
|---|---|
| Cost per month | $6.57 |
| Cost per day | $0.216 |
| Energy per day | 1.2 kWh |
| Energy per year | 438 kWh |
Tips and common mistakes
Your real rate is often higher than the headline. Delivery charges, fees and taxes can add 30-50% to the per-kWh energy price. Dividing your bill's total by the kWh billed gives the true average. Time-of-use plans charge more at peak hours, so price peak-time appliances at the peak rate.
Biggest offenders are usually resistance heating (space heaters, water heaters, dryers), older refrigerators and freezers, pool pumps and always-on PCs.
Frequently asked questions
How much does a 1500W space heater cost to run?
At $0.18/kWh, running at full power for 8 hours uses 12 kWh, about $2.16 a day or roughly $65 a month. The thermostat cycling it off reduces that.
How much electricity does a refrigerator use?
A modern ENERGY STAR full-size fridge uses roughly 350-650 kWh a year. That's about $60-$120 at $0.18/kWh. Pre-2000 models can use twice that.
What is a kWh?
One kilowatt-hour is 1,000 watts for one hour, e.g. a 100 W bulb for 10 hours.
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Estimates for planning only, based on the assumptions shown. Real-world performance varies with equipment, temperature and installation. Updated October 19, 2026. See our methodology.