PSU Calculator — Find the Right Power Supply for Your PC
Quickly calculate how many watts your PC build needs, including CPU, GPU, storage, fans, overclocking headroom, efficiency rating guidance, and future upgrades.
PSU Calculator
Calculate power supply requirements with efficiency recommendations
Input Your Configuration
PSU Analysis Results
Select your components to see analysis results
How the PSU Calculator Works
We add typical draw per component (CPU TDP class, GPU consumption, drives, RAM, cooling, extras) then layer buffers for transient spikes, overclocking, and aging. We target operating the PSU at ~50–70% load for efficiency and fan acoustics.
Total Wattage = CPU + GPU + RAM + Storage + Cooling + Extras
Recommended PSU ≈ Total × (1 + OC %) × (1 + Age %) rounded up.
Extremely oversized PSUs may run outside their peak efficiency curve at idle. Balance headroom with efficiency.
What Factors Affect PSU Wattage
CPU & GPU
Stock vs overclocked CPUs and single vs multi-GPU change draw dramatically. Modern GPUs also have transient spikes 2–3× their rated TBP.
Storage & Memory
SSDs are light (≈5–8W each) while HDDs and enterprise drives add more, especially during spin-up. RAM sticks add a few watts each.
Cooling & Peripherals
AIO pumps, multiple fans, USB devices, capture cards, and RGB can collectively add tens of watts. Budget for them.
Future Upgrades
Leave headroom for an extra drive, more RAM, or a faster GPU later. Aging capacitors also slightly reduce available output.
PSU Quality Matters — Not Just Wattage
Look for strong voltage regulation, low ripple, proper protections (OCP/OVP/OTP/OPP/SCP), and reputable OEMs. Efficiency badges are only part of the picture.
- 80 PLUS: Bronze → Gold → Platinum → Titanium (efficiency and usually better components).
- Rails & connectors: ensure EPS 8-pin, PCIe 8/12-pin counts, and ATX 3.0 / PCIe 5.1 support for new GPUs.
- Modular vs non-modular: modular helps cable management and airflow; non-modular can be cheaper.
- Warranty & reviews: prioritize brands with good testing data and longer warranties.
Recommended Headroom & Rules of Thumb
| Build type | Typical GPU | Suggested PSU | Notes |
|---|---|---|---|
| Office / HTPC | iGPU / low-profile | 300–400 W | Quiet, efficient; plenty for peripherals. |
| 1080p mid-range gaming | RTX 3060 / RX 7600 | 500–650 W | Headroom for extra drives and RGB. |
| 1440p / 4K single GPU | RTX 4070–4080 / RX 7900 | 650–850 W | Allows transient spikes and mild OC. |
| High-end OC | RTX 4090 / halo GPUs | 850–1000 W | Use quality 80+ Gold/Platinum; ensure 12VHPWR cable. |
| Multi-GPU / workstation | Dual GPUs | 1000 W+ | Consider server-class PSUs and dedicated circuits. |
Rule: if the calculator suggests 570 W, buy a 650 W unit; always round up to the next standard size.
Common Mistakes & Myths
- Myth: "Bigger PSU = better performance." Truth: performance doesn't scale with wattage; stability and efficiency do.
- Mistake: ignoring efficiency/quality. Voltage stability and protections matter as much as wattage.
- Mistake: forgetting case size and connectors. Ensure the PSU fits (ATX/SFX) and has the right cables.
- Myth: calculator outputs are exact. Real draw varies by model, silicon lottery, and workload.
- Mistake: no headroom for upgrades or transient spikes; plan 20–30% buffer.
Sample Build Wattage (Real-world-ish)
| Build | Example parts | Est. draw | Recommended PSU |
|---|---|---|---|
| Basic office | iGPU, 2×8GB RAM, 1×SSD | 180–220 W | 300–400 W 80+ Bronze |
| 1080p gaming | i5/R5 + RTX 3060, 3 fans | 300–360 W | 550–650 W 80+ Gold |
| 1440p gaming | i7/R7 + RTX 4070/7800 | 380–470 W | 650–750 W 80+ Gold |
| 4K / high-end | i7/R9 + RTX 4080/7900 XTX | 480–620 W | 750–850 W Gold/Platinum |
| 4090 OC build | i9 + RTX 4090, AIO | 650–750 W | 850–1000 W Platinum |
| Dual-GPU / workstation | 2× prosumer GPUs | 800–1200 W | 1000–1500 W Platinum/Titanium |
FAQ — PSU Calculator & Power Supply Guide
Is it safe to use a PSU with more wattage than needed?
Yes, as long as it's quality. It will only draw what the PC needs, but massive oversizing can reduce efficiency at low loads.
How much headroom do I need?
20–30% covers transient spikes, overclocking, and future add-ons. Very spiky GPUs (e.g., 4090) may warrant 30–35%.
Does PSU brand matter?
Absolutely. Look for reputable OEMs, good reviews, protections, and solid warranties.
Does PSU wattage affect FPS?
No. A stable PSU prevents throttling or shutdowns, but wattage itself doesn't add FPS.
How to account for overclocking and RGB?
Use the OC slider and extras field to add realistic buffer for pumps, fans, controllers, and lighting.
Ready to optimize the rest of your build?
Size your PSU here, then check frame rates and balance your CPU/GPU with our FPS Estimator.
Prefer quality over pure wattage. Stable power keeps your rig healthy.