Your PC just crashed mid-game. You’ve updated the drivers, reseated the GPU, and stress-tested the CPU — everything checks out. The real culprit is almost always the power supply, and it’s the last thing most builders think to check.
An undersized PSU doesn’t always fail loudly. It trips its protection circuit during a millisecond power spike — the kind that happens every time your GPU starts rendering a new frame — and your system dies instantly. No warning. No error code. Just a black screen.
This PSU calculator is built to catch that before it happens. Enter your CPU, GPU, RAM, storage, and cooling setup below. We apply real transient spike multipliers from Cybenetics lab data — not just spec-sheet TDP values — and factor in your PSU’s efficiency rating and age. What comes out is a wattage recommendation you can actually trust, along with a confidence score and specific PSU models to buy.
PC Power Supply Calculator
Enter your components below and get an estimated PSU wattage recommendation — with a step-by-step breakdown and example products. Takes about a minute.
Not sure which PSU to buy? Select your components above and click Check Your Power — we’ll show an estimate using the stated sizing rule.
0W
| Step | Rule | Displayed as |
|---|---|---|
| 1 | Total selected component watts | Component total |
| 2 | Multiply component total by 1.25 | Estimate before rounding |
| 3 | Round up to the next listed standard PSU size | Recommended PSU |
GPU: Not selected
Input and PSU notes
The recommendation is an estimate: the calculator totals the selected component wattages, multiplies that total by 1.25, adds any optional upgrade buffer, and rounds up to the next listed standard PSU size. This is the only sizing rule used.
Source status: entries without an opened source URL are marked unverified. Per-model source status is shown for selected inputs.
Wall draw is not calculated by this tool and is never added to the recommendation.
Important: All results are estimates based on the listed inputs and assumptions. Actual draw varies by hardware revision, BIOS power limits, cooling setup, and workload. For professional workstations or mission-critical builds, verify peak draw with HWiNFO under a real production load before buying.
Affiliate note: Product links may earn a small commission at no extra cost to you. The wattage estimate is calculated from your inputs before any products are shown. Always verify prices before purchasing.
Frequently asked questions