How Much Electricity Does a Desktop Computer Use?

Estimate the monthly electricity cost of a desktop computer from its components, usage pattern, and your local electric rate.

4 min readUpdated July 25, 2026WattPocket
A homeowner reviews a household budget at a desktop computer.

Related wattage and runtime estimate

This supporting tool converts watts and equivalent full-power hours per day into daily, 30-day, and yearly energy costs. It does not replace the guide-specific formula below.

A typical desktop with monitor uses 100 to 200 watts during active work and 30 to 60 watts at idle. This estimate splits 4 hours of active use and 2 hours of idle time. Gaming PCs draw substantially more; see the gaming PC guide for that case.

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$6.78/ month
$0.23/ day
$82.48/ year

This setup uses about 36 kWh in a 30-day month.

01

Component power adds up

A typical office desktop with integrated graphics uses 60 to 120 watts under normal workloads. Adding a dedicated graphics card, multiple drives, or a high-wattage power supply can push active draw to 200 to 400 watts. The monitor adds another 20 to 60 watts.

Sleep and hibernate modes drop power to 1 to 5 watts. Enabling aggressive sleep timers can cut idle energy by 80 percent or more.

Formuladaily kWh = (active watts × active hours + idle watts × idle hours + sleep watts × sleep hours) ÷ 1,000
02

Typical office desktop monthly cost

At an illustrative 18 cents per kWh, a 120-watt desktop with a 30-watt monitor used actively for 6 hours and idling for 2 hours per weekday uses about 1.1 kWh per weekday. Over 22 workdays that is roughly 24 kWh, or about $4.30 per month. Weekends in sleep mode add pennies.

  • Set the OS to sleep after 15 to 30 minutes of inactivity.
  • Turn off the monitor when stepping away for more than a few minutes.
  • Use a smart power strip to cut peripheral power when the computer sleeps.
03

Gaming and workstation workloads are different

Sustained rendering, compiling, or gaming can push a high-end desktop to 400 to 600 watts for hours at a time. For those use cases, see the gaming PC guide. A desktop used for both work and heavy compute should be estimated by splitting hours between workloads.

Rate source and limits

The default rate is the EIA U.S. residential average for April 2026, retrieved July 16, 2026. It is an average revenue per kilowatt-hour, not a quote for your utility plan. Fixed fees, taxes, tiers, and time-of-use prices can change the bill.

Open the EIA source