Power Supply Calculator
Select your components and instantly get the recommended PSU wattage for your build.
Choose Your Components
Please note that the Wattage Calculator only provides an indication of the minimum power that your system requires. In some circumstances, e.g., high-end graphics cards, SLI, or Crossfire, we advise users to purchase a higher wattage than the recommendation to avoid potential problems. Should you have any questions or concerns, please contact our Technical Support.
What is a PSU Wattage Calculator?
A PSU wattage calculator estimates the minimum power supply wattage your desktop PC needs based on the components you select. It sums the power draw of your CPU, GPU, memory, storage, fans and other peripherals, then recommends a PSU size with headroom for peak loads and future upgrades.
Selecting the right PSU is critical: an undersized unit can cause crashes, instability or premature wear; an oversized one wastes money and runs inefficiently at low loads. Our XERON PSU calculator covers popular Intel and AMD CPUs, NVIDIA and AMD graphics cards, plus RAM, storage, PCIe cards, optical drives and case fans.
Why is PSU Wattage Important?
Getting the right PSU size protects your build and improves long-term stability. Key scenarios:
Stability & Safety
A PSU sized too close to peak load may crash under gaming, rendering or multitasking spikes. Extra headroom prevents shutdowns and protects components.
Energy Efficiency
PSUs are most efficient between 40% and 60% load. The right size keeps your unit in its sweet spot, reducing electricity waste and heat.
Future Upgrades
A PSU with headroom supports a stronger GPU or more drives later, without needing a replacement.
Understand 80 Plus PSU Efficiency Ratings
| 80 Plus Rating | Efficiency at 50% Load | Typical Use |
|---|---|---|
| Standard | 80% | Basic office PCs, low-wattage builds |
| Bronze | 85% | Mainstream desktops, entry gaming |
| Silver | 88% | Mid-range systems, quieter operation |
| Gold | 90% | Gaming rigs, content creation, recommended |
| Platinum | 92% | High-end workstations, low heat, quiet fans |
| Titanium | 94% | Enthusiast and server-grade builds |
Common PSU Sizing Mistakes to Avoid
Buying Exactly the Recommended Wattage
Our result is a minimum. Add 20-30% headroom, especially for high-end GPUs, overclocking or dual-GPU setups.
Ignoring Rail Load
Modern PSUs are single-rail, but verify the +12V rail can deliver enough amps for your GPU + CPU combined.
Choosing Cheap No-Name Units
A cheap 850W PSU can be worse than a reputable 550W. Always pick a certified brand with protective circuits (OVP/OCP/SCP).
Forgetting Peripherals
RGB strips, extra fans, USB hubs and external drives all draw power. Add them in the calculator for an accurate total.
Frequently Asked Questions
Add 20-30% for typical builds. For overclocking, high-end GPUs (RTX 4090 / RX 7900 XTX class), or SLI/Crossfire, add 40-50%. A 500W recommendation usually means a 650W or 750W PSU is the practical choice.
No. An oversized PSU runs at a low load percentage, which drops efficiency and wastes money. Most PSUs are most efficient at 40-60% load. Choose a size that keeps your typical load in that range.
Gold is the sweet spot for gaming and workstations: high efficiency, reasonable price, low heat. Platinum and Titanium cost more and make sense only for silent builds or systems running 24/7.
It uses official TDP values from CPU and GPU vendors. Real-world power varies with workload, overclocking and efficiency. Treat the result as a solid baseline, not a lab measurement.
Entry gaming (RTX 4060 class): 550W. Mid-range (RTX 4070): 650-750W. High-end (RTX 4080/4090): 850-1000W. Use the calculator above with your exact CPU and GPU for a precise number.
Fully modular is best for airflow and clean builds. Semi-modular is a good balance. Non-modular is cheaper but adds clutter inside the case. For gaming and small cases, choose modular.
Add up the CPU and GPU TDP, then multiply by 1.5-1.8 for headroom. Typical builds need 450-750W; high-end systems with an RTX 5080 or Ryzen 9 typically need 850W or more. Use the calculator above for your exact parts.
Match wattage to your CPU + GPU, check the ATX / SFX size that fits your case, and pick an 80 Plus Gold or higher rating. For modern GPUs, choose an ATX 3.1 PSU with a native 12V-2x6 connector.