Electronics & Office · West
Cost to run a desktop computer in Arizona
At Arizona’s average residential rate of 15.23¢ per kWh, a desktop computer drawing 200W for 8 hours a day costs about $5.19 a month. Change the numbers below to match how you actually use yours.
Quick answer
Based on 200W at a 70% duty cycle (this equipment cycles on and off rather than drawing full power continuously) and 15.23¢/kWh, the Arizona average for May 2026.
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— per year
Why the cost differs in Arizona
Arizona has the 20th cheapest residential electricity of the 51 US states and territories we track, at 15.23¢ per kWh against a national average of 18.44¢. That is -17.4% compared with the national figure. Arizona has abundant utility-scale and rooftop solar, which suppresses midday generation costs, but the state's defining feature is extreme summer cooling demand. Phoenix-area air conditioners run near-continuously through July and August, so annual bills are high even though the per-kWh rate sits near the national average. The retail market is regulated, with most customers on Arizona Public Service or Salt River Project.
For this appliance specifically, the difference works out to a saving of $13.12 a year against what the same desktop computer would cost at the national average rate. Run the identical appliance in Hawaii and it would cost $213 a year; in Idaho it would cost $50.49. That spread of $162 is entirely down to location.
That works out to roughly 3.9% of a typical Arizona household's annual electricity bill - modest individually, though appliances in this range add up.
Arizona sits below the national average, so this desktop computer costs slightly less to run here than it would for a typical US household. How you use it will move the number far more than where you live.
Retail service in Arizona is regulated, so most households pay a tariff set through state rate cases rather than a shopped rate. The state average is a reasonable proxy, though your utility's specific tariff still varies.
| Location | Rate | Per month | Per year |
|---|---|---|---|
| Arizona this page | 15.23¢ | $5.19 | $62.26 |
| US average | 18.44¢ | $6.29 | $75.38 |
| Idaho cheapest state | 12.35¢ | $4.21 | $50.49 |
| Hawaii most expensive | 52.00¢ | $17.73 | $213 |
Arizona electricity rate trend
Rates in Arizona have moved from 15.23¢ to 15.23¢ per kWh over the last twelve months of published data. Nationally, residential rates rose about 6.2% year over year.
2025-06 to 2026-05 · cents per kWh
About running a desktop computer
A general-purpose desktop draws 100 to 200 watts; a gaming machine with a high-end GPU can exceed 600 under load. Idle draw is much lower, so actual cost depends heavily on what you do with it.
What actually changes the cost
- Nameplate wattage is not running cost. This desktop computer draws about 200W when active, but cycles roughly 70% of the time it is switched on, so effective consumption is near 140W.
- Models vary widely, from about 100W to 600W. Check the nameplate on your own unit rather than assuming an average, because the spread is more than 2x.
- If your utility offers time-of-use pricing, shifting this load off-peak can cut its cost substantially without using any less energy.
How we worked this out
The arithmetic is simple and we would rather show it than hide it. Divide watts by 1,000 to get kilowatts, multiply by hours of use and by the duty cycle to get kilowatt-hours, then multiply by your rate:
200W ÷ 1000 × 8h × 70% = 1.120 kWh/day × 15.23¢ = $0.171 per day
One honest caveat: Arizona’s figure is a state average published by the EIA. Your own utility’s tariff, any time-of-use pricing, fixed monthly service charges and local taxes all shift the real number. Put your actual per-kWh rate into the calculator above for a figure that reflects your bill.
Questions about desktop computer running costs
How many watts does a desktop computer use?
A typical desktop computer draws about 200 watts while running, with most models falling between 100W and 600W. Check the nameplate label or manual for your specific unit - the range is wide enough that averages can mislead.
How much electricity does a desktop computer use per day?
At around 8 hours of use a day and a 70% duty cycle, that works out to roughly 1.12 kWh per day, or about 34 kWh a month. Your actual figure depends on your usage and model.
Why does the cost differ so much between states?
Residential electricity rates across the US range from about 12.35 cents per kWh in North Dakota to 46.62 cents in Hawaii - nearly a fourfold difference. The same desktop computer, used identically, therefore costs almost four times as much to run in the most expensive state as in the cheapest.
Is it cheaper to run a desktop computer at night?
Only if you are on a time-of-use or variable tariff. On a flat rate, the time of day makes no difference to cost. If you are on time-of-use pricing, off-peak hours are typically materially cheaper, and shifting this load can reduce its cost without reducing usage.