Recommended PSU
550 W
DC Load
423 W
AC Draw
635 W
Recommended PSU
550 W
DC Load
423 W
With Headroom
508 W
AC Draw
635 W
Rails
2
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Price as of Jul 24, 2026. Product prices and availability are accurate as of the date indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
Inputs
Result
DC = 120+300+3.3 = 423.3W. With headroom: 423.3×1.2 = 508W. AC: 508/0.8 = 635W. Round up to 650W.
Inputs
Result
DC = 60+2.5+10.8 = 73.3W. With headroom: 73.3×1.2 = 88W. AC: 88/0.8 = 110W. Round up to 150W.
Add up watts for each component: W = V × I. Then add headroom (20%) and divide by PSU efficiency (80%). Example: 300W load × 1.2 headroom / 0.8 efficiency = 450W PSU.
| Component | Voltage | Current | Power |
|---|---|---|---|
| CPU | 12V | 10A | 120W |
| GPU | 12V | 25A | 300W |
| RAM (2x) | 3.3V | 0.5A | 3.3W |
| 5 Fans | 12V | 0.3A | 18W |
80 PLUS rated PSUs: White = 80%, Bronze = 82-85%, Gold = 87-90%, Platinum = 92-94%, Titanium = 96%. Higher efficiency wastes less power as heat.
20% headroom is standard for steady loads. For gaming PCs with GPU power spikes, use 25-30%. For servers with UPS, 40% headroom ensures startup current handling.
An oversized PSU works fine but wastes money. PSUs are most efficient at 40-60% load. A 1000W PSU at 200W load runs at lower efficiency than a 500W PSU at the same load.
Read our guide
Read our guide
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Last Updated: Jul 24, 2026
This calculator is provided for informational and educational purposes only. Results are estimates and should not be considered professional financial, medical, legal, or other advice. Always consult a qualified professional before making important decisions. UseCalcPro is not responsible for any actions taken based on calculator results.