How much does it cost to run a PC?

A PC's electricity cost is its average power times the hours it runs times your price per kWh. At €0.25 per kWh, an office PC averaging 60 W costs about €11 a month if it is never switched off; a gaming or workstation PC averaging 300 W, about €55. One workstation we measured at the wall for two months cost €1.50 a day, and two thirds of that was simply being switched on.

Measured from 2026-08-15 to 2026-10-15 on one desktop PC. The figures will be updated as the recording continues.

The formula

• kWh = watts × hours ÷ 1000
• cost = kWh × your price per kWh

A worked example: a PC averaging 300 W around the clock uses 300 W × 24 h ÷ 1000 = 7.2 kWh a day. At €0.25 per kWh that is €1.80 a day, about €55 a month.

What a PC costs, by wattage

At €0.25 per kWh, with a month of 30.44 days. For another price, multiply by your price ÷ 0.25; the table works the same in any currency. What counts is the average over the hours the PC is on, not its peak.

A real PC, two months at the wall

These figures were recorded by PCWattVault with a TP-Link Tapo P110 smart plug that powered the PC alone (no monitors), from 2026-08-15 to 2026-10-15. The PC was on 99% of that time, and the tariff was a fixed €0.22 per kWh. This is one PC, not an average: an Intel Core Ultra 9 285K with two graphics cards (NVIDIA RTX 5090 and RTX 2080 SUPER) and 128 GB RAM, a heavy workstation whose idle draw is far above a typical PC's.

• In total: 60.6 days on, 412.5 kWh, €90.75.
• On average: 284 W. A full day used 6.8 kWh, which cost €1.50; the lightest day used 5.4 kWh, the heaviest 12.1 kWh.
• Hour by hour: the quietest hours (the lowest 5%) drew 192 W, a typical hour 297 W, the busiest 5% 353 W, and the heaviest single hour 791 W.
• Over a year: on around the clock, that is €547 a year. The idle floor alone, 192 W × 24 h × 365 days × €0.22, is about €370: two thirds of the cost.
• Weekdays and weekends cost the same (6.9 against 6.7 kWh a day): this PC runs around the clock.

Where the energy went:

By hour of day, the PC drew about 290–327 W from midnight to 15:00 and 217–238 W from 16:00 to 23:00: its owner's working hours show.

What brings the cost down

• The idle floor matters more than the peaks. Sleep or shut the PC down when you are away: if this one were off 16 hours a day, it would cost roughly €180 a year instead of €547 (an estimate; sleep still draws a few watts).
• Find what keeps it busy. A per-app view shows which programs hold the power up.
• Power plans and Energy Saver change the draw too. A measured follow-up will come in a later article.
• Monitors are extra. The plug here measured the PC alone.

Measure your own

How to measure your PC's power usage on Windows compares the ways to see your own PC's watts. PCWattVault, the app that recorded the figures above, records the cost per hour, day and month with your own tariff: from the PC's sensors, or at the wall with a smart plug, as here.

FAQ

How much does it cost to run a PC 24/7? Average watts × 24 hours ÷ 1000 gives the kWh a day; multiply by your price per kWh. At €0.25 per kWh, a PC averaging 60 W costs about €11 a month, and one averaging 300 W about €55.

Does a PC use much electricity when idle? It can. A small office PC can idle around 20 W, and a gaming PC with a large graphics card near 100 W. The workstation measured here drew 192 W in its quietest hours, and that idle floor makes up two thirds of its cost.

Is it cheaper to turn a PC off or leave it on? Off or asleep is cheaper. Starting up takes a minute or two at normal power and uses no meaningful extra energy.

How much does an hour of gaming cost? A gaming PC drawing 400–600 W uses 0.4–0.6 kWh in an hour: €0.10–0.15 at €0.25 per kWh.

Do monitors count? Not in a PC-only measurement like the one above: a plug measures only what is plugged into it. Add the monitors separately.