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PSU Wattage Calculator
Pick your parts and we'll estimate your system's power draw and the right power-supply size — with sensible headroom built in.
80 Plus Gold recommended
How we calculate it
We add the typical under-load draw of your CPU and GPU to a baseline for the motherboard, RAM, storage, and fans, then add about 30% headroom and round up to the nearest common PSU size (550, 650, 750, 850, 1000, 1200W). Headroom keeps the unit efficient, cool, and quiet, and leaves room to upgrade.
Frequently asked questions
How big a PSU do I actually need?
Add up the wattage your components draw under load, then add roughly 30% headroom. Most single-GPU gaming PCs land between 550W and 850W. Extra headroom keeps the PSU efficient and quiet and leaves room for upgrades.
Is a bigger PSU always better?
No. A massively oversized PSU wastes money and can run less efficiently at very low loads. Aim for a quality unit rated comfortably above your peak draw, not the biggest number you can buy.
What PSU efficiency rating should I look for?
80 Plus Bronze is the sensible floor; Gold is the value sweet spot for most builds. The rating reflects efficiency, not safety — but reputable Gold-rated units are usually well built.
Does this include overclocking?
The estimate assumes stock-to-mild loads. If you plan aggressive CPU or GPU overclocking, size up one PSU tier for the extra draw and transient spikes.
Building a rig? See our PC build guides and GPU reviews.