PC power supply calculator

What it computes

This calculator builds a power budget for a desktop with one CPU and one graphics card. It returns a PSU capacity target, including your reserve and the graphics manufacturer's minimum system recommendation.

It also estimates wall input at that component budget. These are planning figures, not measurements of gaming consumption or idle power.

Choose a listed component or enter custom watts. For an AMD CPU, use its configured package power limit, such as PPT, rather than base TDP alone. For a custom graphics card, enter both board power and its maker's minimum system PSU.

If this is a gift, confirm the exact components first. Our gifts for PC gamers guide explains which upgrades need that information. The broader gifts for gamers guide covers alternatives when you cannot check their machine.

How it works

The component budget adds CPU power, graphics board power and your allowance for everything else.

CPU presets use Intel Maximum Turbo Power: Core Ultra 200S specifications, Core i5-14600K specifications and Core i9-14900K specifications.

Graphics presets use NVIDIA reference TGP figures and AMD Typical Board Power for the RX 9070 XT and RX 9070. The same sources supply minimum system PSU recommendations. All were checked September 14, 2026.

The editable 75 W allowance covers motherboard, RAM, drives, fans, lighting and CPU regulation losses. It is an example, not a specification for every build.

Multiply the component budget by one plus your reserve percentage. Compare that answer with the graphics vendor's minimum, then round the larger number upward in 50 W steps. Those display steps do not mean every capacity is sold.

The default 25% reserve is an editorial assumption. 80 PLUS concerns efficiency, not capacity headroom. Wall input equals the component budget divided by the efficiency fraction. Changing efficiency changes that estimate without changing the capacity target.

Examples

An Ultra 5 245K with RTX 5070 uses 159 + 250 + 75 = 484 W. A 25% reserve gives 605 W. The graphics vendor's 650 W minimum wins, so the target is 650 W. At 90% efficiency, estimated wall input is 537.8 W.

A Core i9-14900K with RTX 5090 gives 253 + 575 + 75 = 903 W. With 25% reserve, that becomes 1,128.75 W, exceeding the 1,000 W vendor minimum. The rounded target is 1,150 W. An available 1,200 W unit could meet capacity, subject to the other checks. Wall input is about 1,003.3 W at 90% efficiency.

A custom 162 W CPU with RX 9070 XT gives 162 + 304 + 75 = 541 W. Its buffered budget is 676.25 W. The card's 750 W minimum sets the target; wall input is about 601.1 W at 90% efficiency.

Limits

This is not a simulation of short power spikes. Intel's datasheet distinguishes sustained Maximum Turbo Power from brief excursions that can exceed it.

Check your exact graphics card, changed power limits, PSU transient support, connectors and case fit. A wattage result alone cannot establish compatibility. Efficiency varies with load and mains voltage.

Integrated graphics count within the CPU budget. Multiple CPUs or discrete graphics cards are outside this tool's scope. Entering zero for an unknown custom-card PSU minimum disables that comparison and produces a note.