PSU Calculator

Size your power supply before you buy parts — CPU + GPU wattage with safety headroom.

Estimate PSU wattage

How it works

The tool maps your CPU and GPU to typical TDP bands used by our power analysis tab, adds a base system allowance (~100W), then recommends a PSU with about 25% headroom rounded to common wattage steps (450W, 550W, 650W, 750W, 850W, …).

Data sources

Component lists come from the same hardware database that powers the bottleneck calculator (hundreds of CPUs and GPUs). TDP bands are planning estimates aligned with common manufacturer guidance — not a substitute for your exact SKU’s power specification sheet. See also our methodology and disclaimer.

FAQ

How does this PSU calculator estimate wattage?

It estimates CPU and GPU TDP from model families, adds ~100W for motherboard, fans, storage, and other parts, then applies 25% headroom and rounds up to common PSU sizes.

Should I buy the minimum or recommended wattage?

Buy the recommended wattage. The minimum is a floor for efficiency and transient spikes; recommended headroom keeps the PSU in a healthier load range and leaves room for a GPU upgrade.

Does a higher wattage PSU use more electricity?

No. A larger PSU only draws what the system needs. Efficiency curves usually favor running a quality unit around 40–70% load rather than near its limit.

Do I need an ATX 3.0 / 12V-2x6 connector?

Newer high-end NVIDIA cards prefer native 12V-2x6 / ATX 3.x supplies. If your GPU requires that connector, prioritize a modern unit even if the wattage number looks similar to an older PSU.

How accurate is this compared to brand PSU calculators?

It is a planning estimate based on the same component database used by our bottleneck calculator. Exact draw varies by silicon lottery, overclocks, and peripherals — treat the recommendation as a safe sizing guide, not a lab measurement.

Related guides

Also check CPU/GPU balance

Open bottleneck calculator

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