⚡ Desktop PSU Calculator

dommytools online! PC Power Supply Calculator

Choose your CPU and GPU, enter component counts, and get an estimated system power draw and recommended PSU size.

Your PC Components

Wattage values are estimated automatically. You only need to enter counts where applicable.

⚙️ Processor
🖥️ Graphics Card
💾 Memory & Storage
Power / RAM stick
5 W
RAM total
10 W
Power / SSD
5 W
SSD total
5 W
Power / HDD
8 W
HDD total
8 W
🌀 Cooling, RGB & Accessories
Power / fan
2.5 W
Fan total
12.5 W
Power / RGB device
3 W
RGB total
9 W
Power / card
20 W
PCIe total
0 W
Power / USB device
5 W
USB total
10 W
🧩 Motherboard
Estimated motherboard power
60 W
A baseline estimate for the motherboard, chipset, VRM and onboard devices. Actual draw varies by platform and connected hardware.

PC Power Supply Calculator

Build your PC with confidence using our free PC Power Supply Calculator. Estimate your computer's total power consumption and find the recommended PSU wattage for gaming PCs, workstations, home computers, and servers. Simply select your CPU, graphics card, storage devices, cooling fans, RGB lighting, and other hardware to receive an accurate wattage estimate and a recommended power supply size.

What is a PSU Calculator?

A Power Supply Calculator estimates the total power required by your computer components. Choosing the correct PSU ensures system stability, efficient performance, and provides enough headroom for future upgrades.

A quality power supply with sufficient wattage helps prevent unexpected shutdowns, improves efficiency, and supports demanding hardware such as modern graphics cards and high-performance processors.

How to Use This Calculator

  1. Select your processor (CPU).
  2. Select your graphics card (GPU).
  3. Add RAM modules.
  4. Select SSDs and hard drives.
  5. Add cooling fans and liquid coolers.
  6. Select RGB lighting and accessories.
  7. Include PCIe cards or USB-powered devices if required.
  8. View your estimated system power draw and recommended PSU wattage.

What You'll Get

⚡ Estimated Power Usage

Total system power consumption under load.

🔌 Recommended PSU

Suggested PSU wattage with safety headroom.

📈 Upgrade Ready

Extra capacity for future hardware upgrades.

🖥 Component Breakdown

See how much power each component contributes.

Components Included

ComponentExamples
ProcessorIntel Core, AMD Ryzen
Graphics CardNVIDIA GeForce, AMD Radeon
MemoryDDR4 / DDR5 RAM
StorageSSD, NVMe SSD, HDD
CoolingCase Fans, Air Cooler, AIO Liquid Cooler
MotherboardATX, Micro ATX, Mini ITX
AccessoriesRGB, Capture Cards, USB Devices, PCIe Cards

Why Use a PSU Calculator?

Prevent Power Issues

Avoid crashes caused by an underpowered PSU.

Save Money

Buy a PSU that fits your build without overspending.

Support Future Upgrades

Leave extra wattage for new GPUs or storage devices.

Improve Efficiency

Choose a power supply that operates efficiently under normal loads.

Choosing the Right Power Supply

  • Choose a PSU with 20–30% additional capacity beyond your estimated load.
  • Look for 80 PLUS Bronze, Gold, Platinum, or Titanium efficiency ratings.
  • Select trusted PSU manufacturers with good reliability and warranty support.
  • Ensure the PSU provides the required PCIe and CPU power connectors.
  • Consider future graphics card upgrades before purchasing.

Frequently Asked Questions

Is this PSU Calculator free?

Yes. You can calculate unlimited PC builds at no cost.

How accurate is the wattage estimate?

The estimate is based on the selected hardware and typical power consumption. Actual usage may vary depending on workload and overclocking.

Should I buy a larger PSU than recommended?

Yes. Choosing a PSU with additional headroom is generally recommended for stability and future upgrades.

Does a higher wattage PSU consume more electricity?

No. Your computer only draws the power it needs. A higher-rated PSU simply provides more available capacity.

Can I calculate gaming PC power requirements?

Yes. The calculator is suitable for gaming PCs, workstations, home computers, and custom desktop builds.

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