Computers & Laptops

Gaming PC Power Calculator

What a gaming build draws and the supply capacity it suggests, from the specifications of the parts you are actually using.

25 inputs Free, no sign-up

Your figures

Total board power, from the card maker's specification for your exact model.

A larger figure than an office machine needs, because a graphics card's transient spikes are what tends to trip an undersized supply. Still a choice rather than a rule.

Try an example

Result

Your result

Enter your figures and the result appears here.

Estimates only. Rates, fees and specifications change. Confirm against the official source before you rely on a figure — see our disclaimer.

About this calculator

In a gaming build the graphics card is usually more than half the power budget. Everything else — the processor, the board, the drives, the fans — matters, but the card is the component that decides which supply you need.

Enter what each part is specified at and this adds them up. Nothing is filled in for you: cards of the same generation span a range of three or four to one, so a number invented for "a gaming GPU" would be wrong for most builds.

How to use this calculator

  1. Enter the graphics card's total board power from its manufacturer's page. Partner cards of the same chip differ, so use the figure for the exact model.
  2. Enter the processor's rated power. On recent parts the sustained boost figure is higher than the base one and is the number that matters here.
  3. Add the board, memory, drives, fans, pump and lighting.
  4. Set the headroom. Forty per cent is this page's starting figure, and it is a choice.

The formula

Total load        = sum of (each component's power x how many)
Suggested supply  = Total load x (1 + headroom / 100)

A larger headroom on a gaming build is not superstition: a modern graphics card can draw two or three times its rated power for a few milliseconds during a load transition, and a supply that cannot ride that will shut down mid-game even though the average is comfortably within its rating.

SymbolMeaningUnit
Board power Graphics card total board power W
CPU power Processor rated power W
Headroom Spare capacity you want %

Worked example

A 320 W card, a 125 W processor, a 50 W board, 12 W of memory, two 6 W drives, six 3 W fans and an 18 W pump:

320 + 125 + 50 + 12 + 12 + 18 + 18 = 555 W
555 x 1.40                          = 777 W

Which points at an 800 W supply, with the transient behaviour still worth checking in a review.

Notes and limits

  • Card makers often publish a "recommended system power" figure. It is a whole-system number with headroom already in it, so do not add it to this total — compare it against the result instead.
  • Transient spikes are the reason a supply that looks adequate on paper can trip. A review that measures transient response is worth more here than a wattage.
  • Overclocking raises both the sustained draw and the spikes, and neither is in the rated figures.
  • This is a wattage and not a recommendation of any particular unit. Connector count, cable length, protections and build quality all matter and none of them is a number this page has.
  • For what the machine costs to run rather than what it needs, use the gaming PC electricity cost calculator.

What this calculation assumes

  • Every wattage is one you entered. No component specification is stored in this page.
  • Everything is assumed to draw its rated power at once - the safe assumption for sizing.
  • Transient spikes above the rated figures are not modelled, and are the usual reason an adequate-looking supply trips.

Frequently asked questions

What PSU do I need for my gaming PC?

Add up your components' rated power and allow headroom. This page does that from the figures you enter; it gives a wattage rather than naming a unit, because which supply to buy also depends on its connectors, protections and transient behaviour.

Why allow more headroom on a gaming build?

Because graphics cards draw far above their rated power for very short periods during load transitions. The average may sit well inside a supply's rating while the spikes trip its protection, which is why a larger margin is usual here.

Should I use the card maker's recommended PSU figure?

As a cross-check, not as an input. That figure already covers a whole system with headroom, so adding it to a component total would count it twice.

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