PSU Calculator & Wattage Checker
Sizing a power supply is about the total draw of the whole system under load, plus sensible headroom for spikes and future parts. It is not just a matter of matching the single TDP figure printed for your graphics card.
Enter your processor, graphics card and planned build details in the PSU calculator below. The recommendation gives you a wattage range to shop within, so you can choose a unit that runs your PC reliably today and still has room for the upgrade you are planning next.
PSU Calculator
Estimate recommended power-supply wattage with sensible headroom for your build.
How PSU sizing works
Start by adding together the power your CPU and GPU can draw under load, because those two parts account for most of a gaming PC’s consumption. Then allow a smaller amount for the motherboard, storage drives, fans, lighting and USB devices.
Next, leave headroom for transient GPU power spikes. Modern graphics cards can briefly draw well above their average load figure, and a supply with no spare capacity may trip its protections in those moments even if the average total looks safe.
Finally, prefer a quality unit from a reputable range over a cheap unit with a bigger number on the box. An 80 Plus rating describes how efficiently a supply converts power at certain loads; by itself it does not prove build quality, protection features or reliability.
Add CPU + GPU first
These two components dominate system draw under gaming load, so base your estimate on them.
Allow for the rest
Motherboard, drives, fans and peripherals add a modest but real amount on top.
Keep sensible headroom
Spare capacity covers spikes, ageing and your next graphics card, without overspending.
Too small vs too big
An undersized or poor-quality power supply can cause shutdowns and restarts under load, instability that is hard to diagnose, and it can block future upgrades because a stronger graphics card may exceed what it can safely deliver.
Going hugely oversized is less dangerous but mainly costs more to buy, and a unit running at a very low fraction of its capacity at idle may operate less efficiently there. Neither extreme directly changes FPS: a power supply supplies stable power, it does not make games render faster.
Before you buy
Check your GPU maker’s recommended PSU wattage for your exact card and treat it as a floor for a quality build. Confirm the connectors your graphics card needs, such as the number of PCIe power leads or a newer high-power connector, and make sure the unit you choose provides them natively.
Cross-check the recommendation against the official NVIDIA GeForce graphics card specifications, and size for the GPU you plan to upgrade to, not only the one you own today, so you do not have to replace the supply again at the next upgrade.
Frequently asked questions
How many watts does a gaming PC need?
It depends mainly on the GPU tier. Many mid-range builds land around 550 to 750 watts, while high-end graphics cards and flagship processors need more. Use the calculator above with your exact parts for a closer figure.
Is 750W enough?
For many mid-range to upper builds, yes. It is a common sweet spot, but always check your specific GPU maker’s recommendation, especially with high-end cards that spike hard under load.
Does a bigger PSU increase FPS?
No. A larger or better power supply provides stable power and room to upgrade; it does not raise frame rates. FPS is set by your CPU, GPU, settings and resolution.
How long does a good PSU last?
Quality units are built to last for years and often carry long warranties, sometimes a decade. Check the warranty and model details for the exact unit you are considering.
Continue checking your build
Return to the homepage and main bottleneck calculator, then check the GPU bottleneck calculator and CPU bottleneck calculator pages to balance the rest of the build. For model-by-model picks, read our guide to choosing the best PSU for your GPU and CPU.
Calculator wattage figures are estimates for planning a build. Actual draw varies with the exact models, workloads, overclocking and connected devices. Confirm connector types and the GPU maker’s own recommendation before you buy.