Size the Supply, Not the Spec Sheet

Every component lists a TDP or typical draw, but adding them up is only the start. This PC power supply calculator applies load-factor and headroom logic so the number you buy is the number that keeps the build quiet, cool, and stable.

Why 30% Headroom

PSUs peak in efficiency between roughly 50% and 80% of rated load, and GPUs can momentarily draw far more than their sustained TDP. Targeting 30% headroom covers both: the unit idles in its efficient band and never hits its limit during transient spikes.

Match the Recommendation

Read the recommended wattage, then pick a reputable unit of that size or the next step up. Higher-rated bronze/gold/platinum tiers mostly reflect efficiency at load — the wattage figure itself is what protects the hardware.