PSU Calculator
Not sure what power supply you need? Select your CPU, GPU, and peripherals below for a minimum and recommended wattage, modeled with real TDPs and transient spikes - not a generic guess. Most builds need less than the internet tells them, and a few need considerably more.
Select Your Components
Peripherals & Storage
Where the numbers come from
The boring part is what every calculator does: sum the real TDPs of your CPU and GPU from our hardware database, add measured-average draw for RAM, drives, fans, and cooling, and put 25% headroom on top so the unit runs in its quiet, efficient 50-80% band instead of pinned at max.
The part most calculators skip is transients. A modern GPU does not draw its rated wattage politely - it spikes to 1.5-2x TDP for milliseconds at a time (bigger cards spike harder; that multiplier is shown in your result), and a boosting CPU overshoots on top of that. Those spikes are why a build that "should" fit a 750W unit can black-screen under load with no error and no warning. The ATX 3.0/3.1 spec exists precisely because of this: a compliant PSU must absorb excursions up to 200% of GPU rated power. We compute your worst-case momentary peak and show it, so the recommendation is built for the machine you actually have, not the one on the spec sheet.
What we do not model: exotic peripherals (capture cards, PCIe accelerators), heavy USB-PD loads, or serious overclocking. If that is your machine, treat our recommendation as the floor and step up one tier.
What PSU do I need? Four real builds, sized
Four common builds through this exact engine, July 2026 - note how the transient peak, not the sustained draw, is what sizes the big rigs:
| Build | Sustained TDPs | Transient peak | Buy this |
|---|---|---|---|
| Ryzen 5 7500F + RTX 5060 | 65W + 150W | ~390W | 450W Gold |
| Ryzen 5 9600X + RTX 5070 | 65W + 250W | ~610W | 550W Gold, ATX 3.x |
| Ryzen 7 9800X3D + RTX 5080 | 120W + 360W | ~960W | 750W Gold, ATX 3.x |
| Ryzen 9 9950X + RTX 5090 | 170W + 575W | ~1,450W | 1200W Platinum, ATX 3.1 |
Yes, a 5090 build momentarily pulls more watts than a microwave. Click any build to load it in the calculator and adjust the peripherals to match yours.
Minimum vs recommended: which number do you buy?
Buy the recommended one. The minimum is the wattage at which everything runs - at full fan speed, with no headroom for the GPU you will inevitably drop in later, on a unit working its hardest every day of its life. The $20-40 between minimum and recommended buys you silence, longevity, and one less thing to replace at upgrade time. The one place we will talk you out of spending: Platinum and Titanium efficiency tiers. On a gaming PC that idles most of the day, the electricity savings over Gold rarely repay the premium - put that money in the GPU.
Reusing an older ATX 2.x unit? It was never rated for modern excursions, so give it more slack than the recommendation - the calculator prints the adjusted figure when it matters. And whatever the wattage, buy a unit from a maker with a reputation to lose. The PSU is the one component that can take everything else with it when it fails, which makes the no-name 850W special the most expensive thing on the shelf.
Full tier-by-tier breakdown in our PSU wattage guide. Building from scratch? Check the CPU-GPU balance first with the bottleneck calculator - a balanced pair sizes the PSU correctly on the first try.
If you came here looking for OuterVision
OuterVision was the internet's default PSU calculator for over a decade before it went dark on 7 September 2025 (the domain has no DNS record at all now - and no, the lookalike site using its name is not it). That date is not a guess: it is the day of its last successful capture in the Internet Archive and the day its registrar record was last touched, which is when the nameservers came off. We built this as a maintained, vendor-neutral replacement: no signup, no house brand of power supplies to nudge you toward, and a hardware database that gets updated daily rather than frozen in 2019. One deliberate difference: we skipped OuterVision's per-stick, per-drive granularity on purpose. Those inputs changed the answer by single watts while GPU transients swing it by hundreds, so we spent the effort where the failure actually happens.
Updating a guide that still links it? We keep a maintained list of dead PC building tools - OuterVision, CPUBoss, GPUBoss and SSDBoss - with what each one did and how it died. Every status there comes from requesting the domain and recording the response, re-checked monthly and dated, and it is free to cite. The re-check is not decoration: hwcompare was on that list until 3 August 2026, when it came back online and we moved it off.
Frequently Asked Questions
How much wattage does my PC actually need?
Your PC needs enough wattage to power all components under peak load, plus headroom for efficiency and power spikes. We recommend at least 25% more than your total estimated draw. For example, a system drawing 500W should use a 650W PSU.
What happens if my PSU is too small?
An undersized PSU can cause random shutdowns, crashes, and system instability - especially under heavy loads like gaming or rendering. In extreme cases, it can damage components. Always go with at least the minimum recommended wattage.
Is it bad to have a PSU that is too powerful?
No. A higher-wattage PSU will not force extra power into your components - it only delivers what they draw. A larger PSU gives you more upgrade headroom, runs cooler, and can be quieter. The only downside is paying more upfront.
What does 80+ Gold certification mean?
80+ certification measures power supply efficiency - how much AC power from the wall gets converted to usable DC power. 80+ Gold is about 90% efficient and is the best value for most gaming builds. Platinum and Titanium are better but cost significantly more.
Should I account for future GPU upgrades when buying a PSU?
Yes. Next-gen GPUs tend to draw more power. Buying a PSU with 200-300W of headroom over your current draw gives you room to upgrade your GPU without replacing the power supply.
Can I calculate PSU wattage for a dual-GPU build?
Yes - open "Beyond the Base Build" in the calculator and add a second GPU. Dual-GPU setups today are mostly AI and rendering rigs rather than gaming SLI, and they change the math meaningfully: two cards can hit their transient power spikes at the same moment, so the calculator sizes for both excursions landing at once. Overclocks, custom water loops, and add-in cards like capture cards live in the same section.
What power supply do I need for my PC?
It depends almost entirely on your graphics card, since the GPU is the largest and spikiest load in a gaming PC. As a rough guide for 2026 builds: an RTX 5060 class card is happy on a quality 450-550W unit, an RTX 5070 wants 550-650W, an RTX 5080 wants 850-1000W, and an RTX 5090 wants 1200W or more. Those numbers already include headroom for transient spikes, which is why they look higher than a simple TDP sum. Use the calculator above with your exact CPU and GPU for a real number rather than a tier estimate, and prefer an ATX 3.0 or 3.1 unit for any current-generation card.
Can a power supply bottleneck your PC?
Not in the way a CPU or GPU does - a PSU does not cap your frame rate. What an undersized or low-quality unit does instead is fail under load: black screens mid-game, sudden reboots with no error, or a GPU that quietly refuses to hold its boost clocks because the rail sags during transient spikes. That last one can look like a performance problem and get misdiagnosed as a bottleneck. If your system crashes specifically under heavy gaming load rather than running slow, suspect the power supply before the CPU or GPU.