PSU wattage calculator for RTX 50 Series
Choose your graphics card, CPU and parts. Get the power supply size to buy, the cables to look for and how much headroom you have for power spikes.
How the wattage is worked out
The calculator adds the board power of your graphics card and the maximum sustained package power of your processor, then allowances for the motherboard, memory, drives, fans, cooler, lighting and add-in cards. Overclocking adds 10 percent to the graphics card and 20 percent to the processor. That total is your estimated peak load. We then add your chosen headroom and round up to the next common power supply size.
For RTX 50 cards the result is never lower than the system power the maker published at launch, so a build that looks light on paper still gets a safe recommendation. Peak load is rare in gaming. Typical draw is lower, and the tool shows both.
Which power supply features matter
| Feature | Why it matters |
|---|---|
| Wattage | Sets how much load the unit can supply. Aim for 60 to 75 percent at peak. |
| ATX 3.1 and 12V-2x6 | Native cable and better spike handling for modern GPUs. See the RTX 5090 power and thermal limits guide. |
| 80 Plus rating | Gold or better wastes less power as heat and usually runs quieter. |
| Warranty and brand | Ten years signals confidence. Choose recognised makers with good independent reviews. |
Not sure which card to power? Try the can my PC run it checker or the GPU comparison tool.
Frequently asked questions
How many watts do I need for an RTX 5090?
NVIDIA recommends at least a 1000W power supply for the RTX 5090. With a high-end CPU, overclocking or many drives and fans, 1000W to 1200W gives safer headroom, and the calculator shows where your own build lands. Choose a unit with a native 12V-2x6 cable.
Is a bigger power supply wasteful?
Not usually, but there are limits. Power supplies are most efficient around half load, and a much larger unit costs more without giving you extra frames. Aim for a peak load of about 60 to 75 percent of the rating, which leaves headroom for spikes without paying for capacity you never use.
What is ATX 3.1 and do I need it?
ATX 3.1 is the current power supply standard. It includes the 12V-2x6 connector and better handling of short power spikes from modern GPUs. You do not strictly need it with an adapter, but for RTX 50 cards a native ATX 3.1 unit means fewer cables, a cleaner build and less risk of a loose connection.
Do GPU power spikes matter when choosing a PSU?
Yes. Modern graphics cards can briefly draw well above their rated power for milliseconds. A quality power supply with enough headroom absorbs these spikes. An undersized or old unit may trip its protection and shut the PC down mid-game, even when average use looks safe.
How accurate is this wattage calculator?
It is an estimate built from manufacturer power figures plus typical allowances for other parts. Real draw depends on your exact models, settings and workload. Use it to pick a sensible size, then check the power supply maker's own guidance and your graphics card's requirements before buying.
Independent site. Not affiliated with or endorsed by NVIDIA, AMD or Intel. Power figures are manufacturer launch values and vary by model. Product names are trademarks of their owners.