Electricity Usage & Cost Calculator
This free electricity cost calculator shows what any appliance costs to run per day, month, and year, using your own rate. No sign-up.
- Free
- No sign-up
- Uses your own rate
- Runs in your browser
- Works on your phone
Your appliances
Find this on a recent bill, usually listed as the "energy" or "supply" charge per kWh.
Estimated cost
Enter your rate to see your estimate.
How this calculator works
Every result on this page comes from one formula applied to what you enter: watts × hours used ÷ 1,000 = kWh, then kWh × your rate = cost. Each appliance row is calculated separately using its own hours and days of use per month, then added together for the totals shown on the right.
Worked example
Say you run a 100-watt device for 5 hours a day, every day, and your rate is $0.1648/kWh (the U.S. average as of 2024, cited below; use your own rate for a real result).
- Daily use: 100 × 5 ÷ 1,000 = 0.5 kWh.
- Monthly use: 0.5 × 30 = 15 kWh.
- Monthly cost: 15 × $0.1648 = roughly $2.47.
Appliance wattage reference
| Appliance | Typical running wattage |
|---|---|
| TV | 65-133 W depending on screen size (19"-36"+); flat-screen average roughly 120 W |
| Refrigerator | roughly 725 W (frost-free, 16 cu ft reference unit) |
| Space heater | 400-1,500 W |
| Window air conditioner | roughly 500-1,500 W depending on BTU rating (5,000-12,000 BTU) |
| Clothes dryer | 1,800-5,000 W |
| Washing machine | 350-500 W |
| Dishwasher | 1,200-2,400 W |
| Electric water heater | 4,500-5,500 W (40-gallon electric resistance tank) |
| Microwave | 750-1,100 W |
| LED light bulb | incandescent 40-100 W typical; a comparable LED replacement runs roughly 15 W for about 800 lumens |
Each appliance above links to its own guide with a built-in cost calculator. For anything not listed, the full appliance wattage database covers more than 50 household appliances.
This calculator uses the standard utility formula (watts × hours ÷ 1,000 = kWh, kWh × your rate = cost) applied to whatever wattage, usage, and rate figures you enter. It does not pull from a live database or a fixed set of assumptions. The appliance wattage reference table above cites the U.S. Department of Energy's appliance energy table (reproduced by Virginia Cooperative Extension) and other government or manufacturer sources named inline, last checked September 2026. We review the reference figures periodically and update this page when a source changes; see the sourcing paragraph on each appliance's own guide page for the full citation. Cedrick Reese built this calculator and checks its output against the formula above by hand whenever the page changes.
Frequently asked questions
How accurate is this calculator?
It's as accurate as the numbers you put into it. The math itself (watts × hours ÷ 1,000 × rate) is exact, but real-world results depend on your appliance's actual wattage (which varies by model and setting), how many hours you really run it, and your exact electricity rate. Use your own utility bill for the rate whenever possible instead of a guess.
Where do I find my electricity rate?
Look at a recent electricity bill for a line item usually labeled something like "energy charge" or "supply charge," shown in cents or dollars per kWh. If your bill only shows a total dollar amount, divide the total electric charges by the kWh used that period to get your effective rate.
Why isn't there a default national average rate filled in?
Electricity rates vary a lot by state, utility, and season, and a stale default would quietly produce a wrong number for almost everyone. Requiring your own rate is what keeps this tool accurate instead of just plausible-looking.
What does "standby power" mean and should I include it?
Standby power (also called phantom load) is the small amount of electricity many electronics draw even when "off" but still plugged in. It typically adds somewhere around 5-10% to a device's real-world usage. It's optional here because not every appliance draws meaningful standby power. A space heater or dryer generally doesn't, while a TV or game console often does.
Related tools
- Estimate your full electricity bill: even if you don't know your exact usage.
- kWh cost calculator: quickly convert between kWh, rate, and cost, or work out your effective rate from a past bill.
- Browse typical wattage by appliance if you're not sure what number to enter.
- Best energy monitors & smart plugs: measure your actual usage instead of estimating it.
This calculator provides estimates based on the figures you enter. Actual electricity costs depend on your specific appliances, usage patterns, and utility rate structure, and may include fixed fees or taxes not reflected here.