How Much Does It Cost to Run a Desktop Computer in the UK? (2026)
Desktop power draw varies more than almost any other appliance. An office mini PC idles at 20 watts, while a gaming rig with a high-end graphics card can pull 500 watts or more under load.
A typical desktop computer (150 W) costs £0.039 per hour, or about £9.48 per month at 8 hours a day in the UK. Average running cost
| Wattage | Per hour | Per day | Per month | Per year |
|---|---|---|---|---|
| Low 60 W | £0.016 | £0.13 | £3.79 | £46.11 |
| Typical 150 W | £0.039 | £0.32 | £9.48 | £115.28 |
| High 500 W | £0.13 | £1.05 | £31.58 | £384.27 |
Formula: watts ÷ 1000 × hours × price per kWh. Typical use is 8 h/day ≈ 438 kWh per year.
One hour of a desktop computer (0.15 kWh) is the same electricity as
- 3.0hours of a fridge
- 3.3hours of a laptop
- 15hours of Wi-Fi
- 17hours of an LED bulb
In the UK, with electricity at 26.3p per kWh (source: Ofgem price cap 1 Oct–31 Dec 2026, 2026-10), a typical desktop computer costs £0.039 per hour and about £115.28 per year at 8 hours a day. Each £1.00 of electricity buys roughly 25.3 hours of use.
How to lower the cost of running a desktop computer
- Enable sleep after 10 to 15 minutes of inactivity.
- A monitor often uses as much as the computer itself. Turn it off when away.
- Limit the power target on your graphics card. A 10 percent cap often costs only a few percent of performance.
- Laptops use a fraction of a desktop's power for everyday tasks.
In standby it draws about 2 W, which adds roughly 18 kWh (£4.61) per year if it is never unplugged.
Is an efficient desktop computer worth it?
Desktop PC with monitor for office work, about 150 W: about 438 kWh a year. Laptop for the same work, about 45 W: about 131 kWh. The difference is worth £80.80 a year in the UK.
- Replacing one that still works pays back in 11.1 years.
- When yours needs replacing anyway, the extra cost of the efficient model pays back in 11.1 years.
Usage assumed: 8 hours a day. Typical prices: £900.00 for the efficient model, £900.00 more than a basic one. Work it out with your own prices
Frequently asked questions
How many watts does a gaming PC use?
Between 300 and 600 watts while gaming, depending on the graphics card. Idle draw is typically 50 to 100 watts.
Does leaving the PC on overnight cost a lot?
At 60 watts idle for 12 hours it uses 0.72 kWh, roughly the cost of a few minutes of a space heater.
Does a bigger power supply use more electricity?
No. The PSU only delivers what the components request. A larger unit just has more headroom.
Compare with
Cost by region
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Canadian provinces
Related appliances
- Computer Monitor30 W typical
- Printer (Inkjet or Laser)30 W typical
- Phone Charger10 W typical
- Cable or Fiber Modem8 W typical
Use the generic electricity cost calculator · Which uses more? Take the quiz