PC Power Supply (PSU) Wattage Calculator
Estimate the power supply wattage your PC build needs based on CPU, GPU, RAM, storage, cooling, overclocking, and daily usage.
System Configuration
Region & Units
Optimal Zone (Amber) — The selected PSU is efficient but running close to its limits under peak transient spikes. — 86.7% of selected PSU capacity
Power Breakdown
Estimated Electricity Cost
Advertisement
Overview
The PC Power Supply (PSU) Wattage Calculator accurately estimates the electrical power requirements of custom desktop computers. Selecting an appropriately rated power supply prevents system instability, unexpected shutdowns, blue screens (BSOD), and long-term hardware degradation caused by overloaded rails during intense gaming or heavy workstation renders.
Formula
The mathematical model computes the peak operational wattage and applies a standard safety multiplier for modern hardware architectures:
Recommended PSU Capacity = Total Component Wattage × 1.30 Where Total Component Wattage = (CPU Wattage × Overclock Factor) + (GPU Wattage × Overclock Factor) + RAM + Storage + Cooling. The 1.30 multiplier provides a critical 30% headroom buffer required to handle transient power spikes common in high-performance graphics cards.
Practical Example
Consider a standard high-end US gaming rig configuration: an Intel Core i7 processor (125W base), an NVIDIA GeForce RTX 4080 Super (320W), 2 sticks of DDR5 RAM (10W total), 2 NVMe M.2 SSDs (14W total), and 6 RGB case fans (18W total).
Total Component Wattage = 125 + 320 + 10 + 14 + 18 = 487W. Recommended PSU Capacity = 487W × 1.30 = 633W. The user should select at least a high-quality 650W or 750W power supply unit.