PSU Calculator - Calculate Power Supply Wattage
Calculate the exact power supply wattage needed for your PC build with appropriate safety margins and efficiency recommendations.
How to Calculate PSU Wattage for Gaming PCs
Choosing the correct power supply unit (PSU) is critical for PC stability and longevity. An undersized PSU causes crashes, shutdowns, and potential hardware damage. An oversized PSU wastes money and energy. Our free PSU calculator analyzes your components to recommend the optimal wattage and efficiency rating.
This tool accounts for your CPU, GPU, RAM, storage devices, and additional components to calculate total system power draw. We add a safety margin and recommend appropriate 80 Plus efficiency certifications (Bronze, Gold, Platinum) based on your build's power requirements and usage patterns.
Safety First
Automatic 25% safety margin included in all recommendations.
Efficiency
Recommendations for 80 Plus Bronze, Gold, and Platinum tiers.
Customizable
Add extra wattage for fans, RGB, and liquid cooling systems.
PC Power Supply Calculator: Easy Steps
- Select your CPU model and GPU from the dropdown menus
- Enter the number of RAM sticks and storage drives
- Add extra wattage for RGB lighting, fans, or other accessories
- Review your recommended PSU wattage and efficiency tier
For gaming builds, we recommend 80 Plus Gold or higher for efficiency and reliability. Learn more in our comprehensive guide on choosing the right PSU for gaming PCs. After sizing your PSU, verify your components are balanced with our Bottleneck Calculator and check expected performance using our FPS Calculator.
System Components
Enter your PC components to calculate power requirements
Why Choosing the Right PSU Matters
The Power Supply Unit is often the most overlooked component in a PC build, yet it's the most critical for overall system health. It converts high-voltage AC power from your wall outlet into the low-voltage DC power your components need.
1. System Stability
Modern GPUs, especially high-end NVIDIA RTX and AMD RX cards, can have "transient spikes"—brief moments where they draw significantly more power than their rated TDP. A quality PSU with enough headroom can handle these spikes without causing the system to crash or reboot.
2. Component Longevity
Cheap or undersized PSUs often have poor voltage regulation and high "ripple" (small fluctuations in voltage). Over time, this unstable power can degrade the sensitive circuits in your CPU, GPU, and motherboard, leading to premature hardware failure.
3. Energy Efficiency
PSUs are most efficient when running at 40-60% of their maximum capacity. By choosing a PSU that's correctly sized for your build, you'll waste less electricity as heat, resulting in a cooler, quieter system and lower energy bills.
Understanding 80 Plus Ratings
Frequently Asked Questions
Why do I need a safety margin for my PSU?
A safety margin ensures your PSU doesn't run at maximum capacity, which can reduce lifespan, increase noise, and decrease efficiency. It also provides headroom for future upgrades.
What's the difference between PSU efficiency ratings?
80+ ratings indicate how efficiently the PSU converts AC power to DC power. Bronze is 82% efficient, Gold is 87%, and Platinum is 90% at typical loads.
Should I consider modular PSUs?
Modular PSUs allow you to connect only the cables you need, improving airflow and aesthetics. They're especially beneficial in smaller cases or clean builds.
Can a bad PSU damage my components?
Yes, a low-quality or failing PSU can send unstable voltage to your components, potentially damaging your CPU, GPU, or motherboard.
How long do power supplies last?
A high-quality PSU can last 7-10 years or more. Most premium PSUs come with 10-year warranties.