How much does it cost to run a desktop computer?
Short answer: A desktop computer drawing 150 watts costs about $0.03 per hour at the U.S. average residential price of 18.31¢ per kWh. Used 6 hours a day, 30 days a month, that is about $4.94 per month and $59.32 per year. In Louisiana, the cheapest state, the same use costs $3.43 a month; in Hawaii, the most expensive, $12.96.
Desktop computer cost calculator
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Hours per day the computer is switched on, including time it sits idle.
Uses 27.0 kWh per month. The starting price is the U.S. residential average; choose your state or type the price from your own bill.
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| Appliance | Usage | Per month | Remove |
|---|---|---|---|
| Total | |||
| Per year |
An ordinary desktop computer with its monitor draws about 150 watts in use. What it costs depends less on the hardware than on whether it is left on when nobody is using it.
Cost by size and setting
Costs below use the U.S. average price and 6 hours a day, 30 days a month.
| Type | Power | Per hour | Per month |
|---|---|---|---|
| Mini PC or all-in-one | 60 W | $0.01 | $1.98 |
| Office desktop with monitor | 150 W | $0.03 | $4.94 |
| Workstation with large monitor | 300 W | $0.05 | $9.89 |
The power supply rating is not the usage
A desktop may have a 500 or 750-watt power supply, but that is the most it can deliver, not what it draws. An office PC doing email and browsing typically uses 50 to 100 watts, plus 25 to 40 for the monitor. Only demanding work, such as video rendering or games, pushes it much higher; see our page on the gaming PC for that case.
Left on or put to sleep
A computer left on around the clock at 100 watts idle uses 72 kWh a month. The same computer asleep uses 2 or 3 watts. For a machine used six hours a day, sleep mode during the other eighteen saves more electricity than any hardware upgrade.
How to lower the cost
- Set the computer to sleep after 15 to 30 minutes of inactivity.
- Set the monitor to switch off after 5 to 10 minutes.
- Shut down at night if it does not need to stay reachable.
- A screen saver saves nothing; it keeps the monitor and graphics card working.
How a desktop computer compares with other appliances
Typical power and use for each appliance, at the U.S. average price of 18.31¢ per kWh. Follow a link for that appliance's own calculator, or compare two side by side.
| Appliance | Power | Typical use | Energy per month | Cost per month |
|---|---|---|---|---|
| Desktop computer | 150 W | 6 hours a day, 30 days a month | 27.0 kWh | $4.94 |
| Laptop | 60 W | 6 hours a day, 30 days a month | 10.8 kWh | $1.98 |
| Gaming PC | 400 W | 4 hours a day, 30 days a month | 48.0 kWh | $8.79 |
| TV | 100 W | 5 hours a day, 30 days a month | 15.0 kWh | $2.75 |
| Wi-Fi router | 10 W | 24 hours a day, 30 days a month | 7.2 kWh | $1.32 |
The math behind the numbers
150 watts ÷ 1,000 = 0.15 kW. 0.15 kW × 6 hours = 0.9 kWh per day. 0.9 kWh × $0.1831 = $0.16 per day. Over 30 days that is 27.0 kWh and $4.94 a month.
Your own figure will differ if your appliance has a different wattage, if you use it more or less, or if your price per kWh is not the national average. Change any of those in the calculator at the top of this page. Our step-by-step guide explains where to find each number.
Cost to run a desktop computer in every state
Based on 150 watts for 6 hours a day, 30 days a month, at each state's average residential electricity price for July 2026.
| State | Price per kWh | Per hour | Per month | Per year |
|---|---|---|---|---|
| Alabama | 16.40¢ | $0.02 | $4.43 | $53.14 |
| Alaska | 28.83¢ | $0.04 | $7.78 | $93.41 |
| Arizona | 15.38¢ | $0.02 | $4.15 | $49.83 |
| Arkansas | 14.33¢ | $0.02 | $3.87 | $46.43 |
| California | 33.61¢ | $0.05 | $9.07 | $108.90 |
| Colorado | 17.00¢ | $0.03 | $4.59 | $55.08 |
| Connecticut | 24.16¢ | $0.04 | $6.52 | $78.28 |
| Delaware | 18.48¢ | $0.03 | $4.99 | $59.88 |
| District of Columbia | 25.21¢ | $0.04 | $6.81 | $81.68 |
| Florida | 15.03¢ | $0.02 | $4.06 | $48.70 |
| Georgia | 16.27¢ | $0.02 | $4.39 | $52.71 |
| Hawaii | 48.00¢ | $0.07 | $12.96 | $155.52 |
| Idaho | 13.73¢ | $0.02 | $3.71 | $44.49 |
| Illinois | 19.22¢ | $0.03 | $5.19 | $62.27 |
| Indiana | 16.73¢ | $0.03 | $4.52 | $54.21 |
| Iowa | 15.99¢ | $0.02 | $4.32 | $51.81 |
| Kansas | 15.27¢ | $0.02 | $4.12 | $49.47 |
| Kentucky | 13.81¢ | $0.02 | $3.73 | $44.74 |
| Louisiana | 12.72¢ | $0.02 | $3.43 | $41.21 |
| Maine | 32.41¢ | $0.05 | $8.75 | $105.01 |
| Maryland | 21.41¢ | $0.03 | $5.78 | $69.37 |
| Massachusetts | 30.49¢ | $0.05 | $8.23 | $98.79 |
| Michigan | 23.05¢ | $0.03 | $6.22 | $74.68 |
| Minnesota | 17.45¢ | $0.03 | $4.71 | $56.54 |
| Mississippi | 14.54¢ | $0.02 | $3.93 | $47.11 |
| Missouri | 16.09¢ | $0.02 | $4.34 | $52.13 |
| Montana | 14.99¢ | $0.02 | $4.05 | $48.57 |
| Nebraska | 13.78¢ | $0.02 | $3.72 | $44.65 |
| Nevada | 12.77¢ | $0.02 | $3.45 | $41.37 |
| New Hampshire | 26.60¢ | $0.04 | $7.18 | $86.18 |
| New Jersey | 25.19¢ | $0.04 | $6.80 | $81.62 |
| New Mexico | 16.09¢ | $0.02 | $4.34 | $52.13 |
| New York | 29.90¢ | $0.04 | $8.07 | $96.88 |
| North Carolina | 15.16¢ | $0.02 | $4.09 | $49.12 |
| North Dakota | 13.41¢ | $0.02 | $3.62 | $43.45 |
| Ohio | 19.45¢ | $0.03 | $5.25 | $63.02 |
| Oklahoma | 14.35¢ | $0.02 | $3.87 | $46.49 |
| Oregon | 15.97¢ | $0.02 | $4.31 | $51.74 |
| Pennsylvania | 21.72¢ | $0.03 | $5.86 | $70.37 |
| Rhode Island | 28.29¢ | $0.04 | $7.64 | $91.66 |
| South Carolina | 15.47¢ | $0.02 | $4.18 | $50.12 |
| South Dakota | 15.37¢ | $0.02 | $4.15 | $49.80 |
| Tennessee | 13.71¢ | $0.02 | $3.70 | $44.42 |
| Texas | 15.88¢ | $0.02 | $4.29 | $51.45 |
| Utah | 13.12¢ | $0.02 | $3.54 | $42.51 |
| Vermont | 23.75¢ | $0.04 | $6.41 | $76.95 |
| Virginia | 17.55¢ | $0.03 | $4.74 | $56.86 |
| Washington | 14.71¢ | $0.02 | $3.97 | $47.66 |
| West Virginia | 15.78¢ | $0.02 | $4.26 | $51.13 |
| Wisconsin | 19.06¢ | $0.03 | $5.15 | $61.75 |
| Wyoming | 14.36¢ | $0.02 | $3.88 | $46.53 |
Frequently asked questions
How much does it cost to leave a computer on 24/7?
A desktop averaging 150 watts would cost about $0.66 a day at the U.S. average electricity price. Idle draw is usually lower than that.
How much electricity does a desktop computer use per month?
About 27 kWh at 150 watts for 6 hours a day, or $4.94 at the U.S. average price.
Should I shut down my computer or put it to sleep?
Either saves most of the energy. Sleep uses 2 to 3 watts and resumes in seconds; shut down uses under one watt.
Sources
- ENERGY STAR: Computers
- U.S. Energy Information Administration, Electric Power Monthly (state electricity prices)
- U.S. Department of Energy, Energy Saver: Appliances and Electronics
Electricity prices are the EIA figures for July 2026. Wattages are typical values; check the label on your own appliance.