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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 £9.36 per month at 8 hours a day in United Kingdom. Average running cost
| Wattage | Per hour | Per day | Per month | Per year |
|---|---|---|---|---|
| Low (60 W) | £0.016 | £0.12 | £3.74 | £45.55 |
| Typical (150 W) | £0.039 | £0.31 | £9.36 | £113.88 |
| High (500 W) | £0.13 | £1.04 | £31.20 | £379.60 |
Formula: watts ÷ 1000 × hours × price per kWh. Typical use is 8 h/day ≈ 438 kWh per year.
In the UK, with electricity at £0.26 per kWh (source: Ofgem price cap 1 Jul–30 Sep 2026, 2026-07), a typical desktop computer costs £0.039 per hour and about £113.88 per year at 8 hours a day. Each £1.00 of electricity buys roughly 25.6 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 (£4.56) per year if it is never unplugged.
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.
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Cost by region
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