💻How much electricity does a computer use?
A computer draws about 50 watts for a laptop up to 300 watts for a desktop. At 6 hours a day and the US-average 17¢/kWh, that’s about $1.53–$9.18 a month ($19–$112 a year) — roughly $0.009–$0.051 an hour while it’s on.
These are estimates, not a meter reading. The wattage and energy figures are typical US ranges and the 17¢/kWh is the national-average rate — the math is exact once you plug in your own wattage and rate. Your real cost depends on the specific unit, your settings and your utility.
Energy and cost, broken down
| Timeframe | Energy (kWh) | Cost @ 17¢/kWh |
|---|---|---|
| Per hour running | 0.05–0.30 | $0.009–$0.051 |
| Per day (6 h) | 0.30–1.8 | $0.051–$0.31 |
| Per month | 9.0–54.0 | $1.53–$9.18 |
| Per year | 110–657 | $19–$112 |
At the US-average 17¢/kWh. On a cheap rate (~11¢) these drop about a third; in California, New England or Hawaii (~33¢+) they roughly double. Ranges reflect the typical span of unit sizes and settings.
Why it costs what it does
What a computer costs to run depends almost entirely on its type. A laptop is remarkably cheap — 20 to 50 watts, less than a light bulb. A desktop runs 100 to 300 watts depending on the graphics card, and a gaming PC under load pulls 300 to 600 watts, monitor included. The processor and GPU are the big draws, so browsing and word processing cost a fraction of what gaming or video rendering does on the same machine. Idle and sleep states use far less than the full-load figure.
How to run it for less
- Sleep or shut down instead of leaving it on 24/7 — an idle desktop still draws 50–100 watts around the clock, which adds up faster than the hours you actually use it.
- A laptop uses a fraction of a desktop's power for the same tasks — for light work it is the cheapest computer to run by a wide margin.
- Enable the OS power-saving/sleep settings so the machine and monitor drop to a few watts when idle rather than staying at full brightness and clock speed.
- Undervolt or cap the frame rate on a gaming PC — the GPU is the biggest draw, and it pulls the most only when you let it run flat-out.
Keep going
Frequently asked
How much electricity does a gaming PC use?▾
A gaming PC pulls 300 to 600 watts under load — several times a normal desktop — because the graphics card alone can draw 200 to 400 watts when a game is running. At 6 hours of gaming a day and the US-average 17¢/kWh that is roughly $9 to $18 a month, versus a couple of dollars for the same hours of web browsing on the same machine. It only draws that much while actually gaming; at the desktop it idles far lower.
Is it cheaper to use a laptop or a desktop?▾
A laptop, by a wide margin. Laptops are built for battery life, so they sip 20 to 50 watts where a desktop uses 100 to 300 for similar tasks. For everyday work a laptop can cost a quarter to a tenth as much to run. A desktop only makes sense on power terms if you need the performance a laptop can't match — and even then, only while it's working hard.
How do I work out what a computer costs to run for my electricity rate?▾
Take the wattage ÷ 1,000 to get kilowatts, multiply by the hours you run it, then by your electricity rate. Find your rate on your bill (total ÷ kWh used) — the US average is about 17¢/kWh, but it ranges from ~11¢ in the cheapest states to 30–42¢ in California, New England and Hawaii. So the same computer costs roughly 35% less on a cheap rate and nearly double on an expensive one than the figures here.
What is the average price of electricity in the US?▾
About 17¢ per kWh for residential customers as a national average (2026). The cheapest states — parts of the Midwest and Pacific Northwest — sit near 11¢, while California, most of New England and Hawaii run 30¢ to over 40¢. Your exact rate is on your utility bill; divide the dollar total by the kWh used, or read the per-kWh charge directly.