Reviewed by: David Chen, Hardware Specialist & Tech Consultant
Building a new PC or upgrading your graphics card? Use our psu power supply calculator to accurately determine the total wattage your system requires to ensure stability, efficiency, and longevity for your components.
psu power supply calculator
psu power supply calculator Formula:
Total Wattage = (CPU TDP + GPU TDP + (RAM × 5W) + (Drives × 10W) + (Fans × 3W) + 50W Motherboard) × 1.25 (Safety Margin)
Formula Source Reference: Intel Power Guide | Corsair PSU Advisor
Variables:
- CPU TDP: The Thermal Design Power of your processor.
- GPU TDP: The maximum power draw of your graphics card.
- RAM Sticks: Standard DDR4/DDR5 sticks use approx 5W each.
- Storage: Mechanical HDDs and NVMe SSDs draw 5-10W under load.
- Safety Margin: A 20-30% overhead is recommended for capacitor aging and transient spikes.
Related Calculators:
What is psu power supply calculator?
A psu power supply calculator is a specialized tool used by PC builders to estimate the total electrical power (in Watts) required by all computer components. Choosing the right PSU is critical because an underpowered unit can cause system crashes, data loss, or even physical damage to your hardware.
Modern high-performance components, especially NVIDIA RTX or AMD RX graphics cards, exhibit “transient spikes”—brief moments where power draw doubles. This calculator includes a built-in safety buffer to ensure your Power Supply Unit (PSU) operates within its most efficient load range (typically 50-80% capacity).
How to Calculate psu power supply calculator (Example):
- Identify your CPU TDP (e.g., Ryzen 5 5600X = 65W).
- Identify your GPU TDP (e.g., RTX 3060 = 170W).
- Add fixed motherboard/Misc power (approx 50W).
- Add RAM (2 x 5W = 10W) and Storage (1 x 10W = 10W).
- Sum the values: 65 + 170 + 50 + 10 + 10 = 305W.
- Apply the 1.25x safety factor: 305W * 1.25 = 381W. Recommended: 450W-500W PSU.
Frequently Asked Questions (FAQ):
Is 80 Plus Gold better than Bronze? Yes, higher ratings mean the PSU converts AC to DC more efficiently, wasting less heat and reducing electricity bills.
Should I buy exactly the wattage I need? No, it is best to buy a PSU with 20-30% more capacity than your peak estimated load for future upgrades.
Do case fans matter in calculation? Individually they draw little (2-5W), but in RGB-heavy builds with 10+ fans, it adds up to 50W+.
Does a higher wattage PSU use more electricity? No, a 1000W PSU only draws what the system needs. If your system needs 300W, the PSU draws ~330W from the wall depending on efficiency.