Enter an appliance's watts (or amps and volts, or kWh) to see what it costs to run. Add several appliances to compare them and estimate your total monthly cost.
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DetailsQuick cost from watts
Per hour
$0.18
Per day
$0.18
Per month
$5.40
Per year
$64.80
1,000 W ÷ 1,000 × 1 hrs × 30 days × 18¢/kWh = $5.40 (30.00 kWh per month)
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ADVICE
Results are estimates based on the watts and hours you enter. Fixed charges, delivery charges, taxes and standby power are not included, so your actual bill will differ. Days per month are capped at 31.
How to Calculate Electricity Cost From Watts
The cost of running an appliance is watts ÷ 1,000 × hours of use × your rate per kWh. A 1,000-watt appliance costs about 18¢ per hour at 18¢/kWh. Run for 1 hour a day over 30 days, that is about $5.40 a month.
Type in a wattage and the calculator shows the cost per hour, day, month and year right away. If you only know the nameplate amps and volts, or a kWh figure from your bill or smart meter, switch the input and it works from those instead.
To see where your money goes, add appliances such as a window AC, refrigerator or space heater. You get a cost for each one, a total for the list, and a ranking from most to least expensive. Set the rate slider to match your own utility bill.
Common Uses: Appliances, Bills and Upgrades
Check what one appliance costs to run
Enter the watts printed on the label and see the cost per hour, day, month and year. Preset buttons cover common wattages like 100 W, 1,000 W and 1,500 W.
Find out which appliances drive your bill
Add the big users, such as a window AC, space heater, clothes dryer and refrigerator, and let the ranking show which ones account for most of the estimated monthly cost.
Turn kWh into dollars
Your bill or smart meter app reports usage in kWh. Enter 2 kWh or 100 kWh and get the dollar amount at your rate.
Compare an old appliance with a new one
Enter the wattage of the old model and the new one with the same hours of use. The difference in monthly cost shows how much an upgrade could save.
Estimate an Appliance's Running Cost in 4 Steps
- Enter the appliance's watts, or switch to amps × volts or kWh if that is what you have.
- Set hours per day and days per month, then drag the rate slider to the cents per kWh on your bill.
- To compare appliances, add them from the presets or create your own entry.
- Read the cost per appliance, the monthly total and the ranking.
Note: Switch to the kWh option if you already know the energy used and only need the cost.
What the Estimate Leaves Out
- The default rate of 18¢/kWh is a national average. Your actual rate depends on your state, utility and rate plan, so set the slider to match your bill.
- Hours per day are capped at 24 and days per month at 31. For a seasonal appliance, work out the monthly cost and multiply by the number of months you use it.
- Air conditioners and refrigerators cycle on and off, so entering their rated watts for 24 hours a day usually overstates the cost.
- Standby (phantom) power is not included. Add a device again with its standby wattage if you want to count it.
- Fixed monthly charges, delivery charges, taxes and fees are not included, so your real bill will be higher than the total shown.
Cost to Run Common Wattages (at 18¢ per kWh)
Cost per hour, and per month for 1 hour of use a day over 30 days. Examples are typical appliances; check the label on yours.
| Power (W) | Per hour | 1 hr/day × 30 days | Typical examples |
|---|---|---|---|
| 5 W | 0.09¢ | $0.03 | Phone charger |
| 15 W | 0.27¢ | $0.08 | LED bulb, Wi-Fi router |
| 40 W | 0.72¢ | $0.22 | Ceiling fan (low), LED lighting |
| 75 W | 1.35¢ | $0.41 | Electric blanket, monitor |
| 100 W | 1.8¢ | $0.54 | Laptop, small TV |
| 150 W | 2.7¢ | $0.81 | Refrigerator (while running), LCD TV |
| 200 W | 3.6¢ | $1.08 | Desktop PC |
| 350 W | 6.3¢ | $1.89 | Gaming PC under load |
| 500 W | 9¢ | $2.70 | Blender, small window AC |
| 700 W | 12.6¢ | $3.78 | Rice cooker, vacuum cleaner |
| 1,000 W | 18¢ | $5.40 | Microwave, hair dryer (low) |
| 1,200 W | 21.6¢ | $6.48 | Coffee maker, microwave (high) |
| 1,500 W | 27¢ | $8.10 | Space heater, electric kettle |
| 1,800 W | 32.4¢ | $9.72 | Hair dryer (high), toaster |
| 2,000 W | 36¢ | $10.80 | Portable heater, large stove burner |
Formula:
watts ÷ 1,000 × hours × rate per kWh. At 1,000 W, one hour is exactly 1 kWh.
From kWh to dollars:
kWh × rate per kWh. At 18¢/kWh, 2 kWh is $0.36, 50 kWh is $9.00 and 100 kWh is $18.00.
The table assumes 18¢ per kWh. Use the rate slider in the calculator to see the figures at your own rate.
Watts, Kilowatts and kWh Explained
How the units fit together, what a typical rate looks like, and why rated watts can mislead.
The short answer: watts ÷ 1,000 × hours × rate
Appliance running cost is watts ÷ 1,000 × hours of use × rate per kWh.
A 1,000 W appliance running for one hour uses 1 kWh, which costs 18¢ at 18¢/kWh.
Multiply by hours per day and days per month to get the daily, monthly and yearly cost.
Watts vs. kilowatts vs. kWh
Watts (W) and kilowatts (kW) measure power, how much an appliance draws at a given moment. 1 kW is 1,000 W.
Kilowatt-hours (kWh) measure energy, the amount used over time, and that is what your utility bills you for.
A 1,000 W heater running for 1 hour uses 1 kWh, and so does a 500 W device running for 2 hours. For 2 kWh, run a 1,000 W hair dryer for 2 hours or a 100 W laptop for 20 hours.
Average U.S. electricity rate and why yours may differ
The U.S. Energy Information Administration expects the national average residential price to be around 18¢ per kWh in 2026.
State averages vary widely, from roughly 11¢ in some states to about 40¢ or more in Hawaii, and your rate also depends on your utility and plan. Some plans charge more during peak hours.
Check your bill for the per-kWh rate, or divide the total by the kWh used for an all-in rate.
Amps, volts and watts
Many labels list amps instead of watts. Watts = volts × amps, so 10 A on a 120 V outlet is 1,200 W, and 10 A on a 240 V circuit is 2,400 W.
Large appliances such as electric dryers and ranges often run on 240 V. Choose the amps option in the calculator and set the volts to 240 for those.
For motors and compressors the real draw can be below amps × volts, so treat the result as an upper estimate.
Rated watts vs. what an appliance really uses
An air conditioner or refrigerator runs hard until it reaches the set temperature, then cycles down or off. Multiplying rated watts by every hour of the day tends to overstate the cost.
For a better figure, use the yearly kWh on the appliance's EnergyGuide label: divide by 8,760 hours and multiply by 1,000 to get average watts, then enter that number.
Common Mistakes That Skew Appliance Cost Estimates
Using rated watts for a refrigerator or AC as if it ran nonstop
The wattage on the label is the maximum draw. A compressor cycles on and off, so entering that number for 24 hours a day gives a cost well above what the appliance actually uses.
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Entering a whole season's days as days per month
Typing 90 days for a space heater or fan makes the monthly cost look far bigger than it is, because the field is meant for days in a single month.
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Leaving the rate at 18¢ when your rate is very different
Rates run from the low teens to above 30¢ in some places, so the default can put the result off by dollars per month for a heavy appliance.
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Forgetting standby power
A TV, game console or set-top box draws a small amount while it appears to be off. Counting only the hours it is on understates the yearly cost.
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Comparing the total to a utility bill and expecting a match
The calculator prices only the energy used by the appliances you enter. A bill also has fixed charges, delivery charges, taxes and fees.
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Electricity Cost FAQ
Q.How much does a 1,000-watt appliance cost to run per hour and per month?
A. At 18¢ per kWh, a 1,000-watt (1 kW) appliance costs about 18¢ for each hour it runs. Used 1 hour a day for 30 days, that comes to about $5.40 a month, or about $64.80 over 12 months. Because 1,000 W equals 1 kW, one hour of use is exactly 1 kWh. Enter any wattage and usage time in the calculator to run the same math for your own appliance.
Q.What is the formula for appliance electricity cost?
A. Cost = watts ÷ 1,000 × hours of use × rate per kWh. For example, a 700 W appliance running 1 hour at 18¢/kWh uses 0.7 kWh and costs 0.7 × $0.18 = about 12.6¢. The calculator multiplies this by your hours per day and days per month, then shows the cost per hour, day, month and year at the same time.
Q.How do I turn amps into watts?
A. Multiply amps by volts. A 10-amp load on a 120 V circuit is 1,200 W; on a 240 V circuit the same 10 amps is 2,400 W. Switch the calculator to the amps option, enter amps and volts, and it converts to watts for you. This treats the appliance as a simple load, so for motors and compressors the real draw can be lower than amps × volts.
Q.How much does 100 kWh or 2 kWh cost?
A. Switch the calculator to kWh and enter the amount. At 18¢ per kWh, 2 kWh costs $0.36 and 100 kWh costs $18.00. The calculator also shows how many hours that energy would run a 1,000 W appliance (2 kWh is about 2 hours) and a 100 W appliance (2 kWh is about 20 hours).
Q.What electricity rate should I use?
A. The U.S. Energy Information Administration expects the 2026 national average residential price to be around 18 cents per kWh, so the calculator starts at 18¢. Rates differ a lot by state and utility, from roughly 11¢ in some states to about 40¢ or more in Hawaii. For a closer estimate, look at your own bill and set the slider to your rate, or divide your total bill by the kWh you used to get an all-in rate that includes delivery charges.
Q.How do I calculate the cost of something that runs 24 hours a day, like a refrigerator?
A. Enter 24 under hours per day and 30 under days per month. Keep in mind that a refrigerator compressor cycles on and off, so its nameplate wattage overstates what it uses on average. A better input is the yearly kWh from the EnergyGuide label, divided by 8,760 hours and multiplied by 1,000 to get average watts. The refrigerator preset in the calculator uses a typical average, not a rated maximum.
Q.Can I enter more than 31 days a month?
A. No. Days per month tops out at 31 and hours per day tops out at 24, because the calculator works out a monthly cost. For a seasonal appliance such as a space heater, find the monthly cost first and then multiply by the number of months you use it.
Q.Does the calculator include standby (phantom) power?
A. No. It only prices the watts and hours you enter. To include standby draw, add the device a second time with its standby wattage and the hours it sits idle, then add the two costs together.
Q.Can I compare several appliances at once?
A. Yes. Add appliances from the presets or create your own. Each one gets its own hourly, daily, monthly and yearly cost, and the page totals everything into an estimated monthly bill, yearly cost and monthly kWh. A ranking shows which appliances cost the most.
Q.Is the information I enter sent anywhere?
A. No. The calculation runs in your browser and nothing you enter is sent to our servers. Your list is not saved, so it is cleared when you close or reload the page.
Q.Why is my utility bill higher than the calculator's total?
A. The calculator only prices the energy used by the appliances you list. A real bill also includes fixed customer or service charges, delivery charges, taxes and fees, plus usage from appliances you did not enter. Use the results to compare appliances and see where savings are possible, not to predict the exact bill.
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