PSU Wattage Calculator
Add estimated component loads to see a power-supply planning range. Wattage and headroom alone do not establish hardware compatibility.
Recommended PSU range
Conservative planning estimate, not a compatibility guarantee. Check connectors, transient loads and manufacturer recommendations.
Formula checked · NumberSwift · Review process
How this calculator works
Add your CPU and GPU peak estimates to the remaining system load, then allow 30–50% extra capacity. This margin can help with transient demand and future additions. Wattage alone cannot determine a suitable PSU: connector count, rail design, efficiency, physical dimensions and manufacturer requirements also matter.
Formula
estimated load = CPU + GPU + other; headroom = 30–50%
Assumptions & limitations
Conservative planning estimate, not a compatibility guarantee. Check connectors, transient loads and manufacturer recommendations.
Worked example
A 450 W load suggests roughly 600–700 W.
Our approach to calculations ↗Common questions
Does this prove a PSU will be compatible?
No. Connector types, transient loads, rails, size and the component manufacturer’s guidance also matter.
Why add 30–50% headroom?
It is an explicit conservative planning range, not a calibrated hardware compatibility rule. Check the actual system recommendations.
Are efficiency losses added to the component load?
The PSU rating describes output capacity. Wall input and PSU efficiency are different quantities; this estimate sums component-side demand.