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⚡ PSU Wattage Calculator

Find the exact power supply wattage your PC needs, with safe headroom.

🧮 58 Tools 🗂️ 10 Categories ⚡ Instant & free

Your components

Power requirements

Recommended PSU

get a quality unit rated at least this high

Idle draw

Peak draw

PSU class

Includes a headroom of % for transient power spikes. Always choose an 80 PLUS Bronze or better unit from a reputable brand.

How to use

  1. 1

    Pick your CPU

    Select your processor to include its typical power draw (TDP).

  2. 2

    Pick your GPU

    Select your graphics card — the single biggest consumer in a gaming PC.

  3. 3

    Add your components

    Include RAM, storage drives, fans, RGB and USB devices, plus any overclocking.

About the PSU Wattage Calculator

Why headroom matters

Graphics cards draw far more power in short bursts than their rated TDP — an RTX 4090 can spike past 600W for a few milliseconds. A quality PSU with 20-30% headroom absorbs these spikes safely, keeps fans quiet and leaves room for future upgrades.

Choosing the right PSU

Once you know the wattage, pick a unit from a reputable brand with an 80 PLUS Bronze or better rating and the right modular cables for your build. Never cheap out on the power supply — it protects every other component in your PC.

Frequently asked questions

No. A far larger PSU than needed is wasteful and runs less efficiently. The sweet spot is a unit rated for about 20-30% more than your peak draw, which is exactly what this calculator recommends.

Yes. Overclocking raises both CPU and GPU power draw. Use the overclock slider to add the correct buffer.

80 PLUS Bronze, Silver, Gold, Platinum and Titanium rate how efficiently the PSU converts AC to DC. Efficiency affects running cost and heat, not the wattage you need.

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