Recommended power supply
800W
80 PLUS Gold
This size covers an estimated 593W peak, including 64W for GPU transients, plus your 30% upgrade margin.
Component load
529W
Peak PSU load
74.1%
Reserve at peak
207W
PC build power planning
PSU Calculator
A PSU calculator estimates the power-supply wattage a PC needs from its CPU, GPU, storage, cooling, memory, and accessories. Add transient-spike protection and upgrade headroom to get a practical standard PSU size.
PC components
Use manufacturer power limits when available.
Power breakdown
Typical gaming load: 424W (52.9%)
CPU105W
Graphics card320W
Memory12W
NVMe drives14W
SATA drives10W
Case fans20W
Liquid-cooling pumps18W
USB and accessories30W
How to size a PC power supply
Start with manufacturer power limits for the CPU and graphics card, then add smaller components. GPU and CPU marketing labels are not identical across vendors, so use maximum board power or package power when possible.
The calculator adds a separate GPU transient allowance before applying your upgrade margin. The final number is rounded up to a commonly sold PSU capacity instead of suggesting an impractical exact wattage.
Frequently asked questions
What is a PSU calculator?
A PSU calculator estimates a PC's maximum power demand from its CPU, graphics card, drives, cooling, memory, and accessories, then adds capacity for short spikes and future upgrades.
How much PSU headroom should I add?
A 20% to 30% margin is practical for most builds. Add more if you plan a major GPU upgrade, heavy overclocking, or many powered accessories.
Is a higher-wattage PSU dangerous for a PC?
No. A PC draws only the power it needs. Quality, protections, connectors, efficiency, and operating load matter more than simply choosing the highest wattage.
What 80 PLUS rating should I choose?
80 PLUS Gold is a strong default for gaming and workstation PCs. Bronze can suit budget systems, while Platinum may pay off for high-power machines that run for long periods.
Why include a GPU transient allowance?
Modern graphics cards can draw brief bursts above their listed board power. A transient allowance helps prevent shutdowns when those short spikes occur.
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