PSU Calculator
Size your power supply the safe way. Pick a CPU and GPU, tune the extras, and get a recommended wattage that accounts for realistic peak draw and transient spikes — then build the rest with live compatibility checking in the Builder.
How the recommendation is calculated
We estimate each component’s realistic peak draw — not its optimistic nameplate TDP — because CPUs boost past their rated power and high-end GPUs spike well above board power for brief moments a supply must ride out. The CPU and GPU dominate; motherboard, memory, drives, fans, and RGB add a smaller baseline. We sum those to an estimated peak load, add buying headroom (more for transient-heavy cards), and round up to the next standard PSU size.
The goal is comfortable headroom, not the biggest number — enough that the unit runs cool and efficient and leaves room for a future upgrade. This is a sizing estimate; always check the GPU maker’s own minimum PSU recommendation too. The builder’s compatibility engine applies the same headroom logic across your whole parts list.
Frequently asked questions
How many watts does my PC need?
Add the realistic peak draw of every component — the CPU and GPU dominate — then leave headroom so the supply isn’t running flat-out. This calculator does that for you: pick a CPU and GPU, adjust drives, fans, and RGB, and it returns a recommended wattage rounded up to a standard PSU size.
Why is the recommendation higher than the parts’ rated TDP?
Nameplate TDP understates real peak power. Intel and AMD CPUs boost well past their rated TDP under load, and modern GPUs draw large millisecond transient spikes above their board power. A good PSU should never run at 100% of its rating, so we size for peak draw plus buying headroom.
What 80 PLUS efficiency rating should I get?
For most builds, 80 PLUS Bronze or Gold is the value sweet spot; Gold is worth it on higher-wattage systems that run heavy loads often. The calculator suggests a tier based on the recommended wattage. Efficiency affects heat and electricity cost, not whether the PC works.
Is a bigger PSU always better?
Up to a point. Headroom is good for stability, longevity, and future upgrades, but a wildly oversized unit wastes money and can run less efficiently at very low load. The recommendation here targets comfortable headroom (roughly 35–45% over estimated peak), not the largest possible size.