Technology
PC Power Supply Calculator
Calculate total system wattage and get a PSU recommendation with proper headroom for your PC build.
Select your components and click Calculate
How is this calculated?
Total System Power = CPU TDP + GPU TDP + RAM + Storage + Fans + Peripherals + Motherboard
Component Power:
RAM: 5W per DDR4 stick, 7W per DDR5 stick
SSD: 5W each | HDD: 10W each
Fans: 3W each | Motherboard: 50-80W
Peripherals: Basic 10W, Moderate 25W, Heavy 50W
Recommended PSU = Total × 1.2 (20% headroom minimum)
For transient spikes (modern GPUs): Total × 1.3
PSU Tier Recommendation:
≤400W: 80+ Bronze sufficient
400-650W: 80+ Gold recommended
650W+: 80+ Gold/Platinum recommendedFAQ
Frequently asked questions about PC power supplies
How much PSU wattage do I need?
Add up all component TDPs and add 20-30% headroom. A typical gaming PC with a mid-range GPU needs 550-650W, while high-end builds with RTX 4090 may need 850-1000W.
What happens if my PSU is too small?
An undersized PSU can cause random shutdowns, system instability, crashes under load, and in worst cases component damage. Transient power spikes from GPUs can trigger overcurrent protection.
What is 80+ certification?
80+ certifies that a PSU is at least 80% efficient at converting AC to DC power. Higher tiers (Bronze, Gold, Platinum, Titanium) indicate better efficiency, less heat, and lower electricity costs.
Is it bad to have too much PSU wattage?
No, an oversized PSU simply runs at lower load (which can be slightly less efficient at very low loads). It's better to have headroom. PSUs only draw what components need.
Should I include peripherals in the calculation?
USB peripherals draw minimal power (2.5-4.5W each). Include them for accuracy but they won't significantly change the recommendation. RGB lighting and multiple fans add up though.
Does RAM affect power consumption?
Each DDR4 stick uses 3-5W, DDR5 uses 5-8W. With 2-4 sticks, RAM contributes 10-32W total — a small but non-zero portion of total system power.