Introduction
A power supply unit (PSU) is one of the most important parts of any PC build. If your PSU is too weak, your computer can crash, shut down, or even damage your parts. If it is too strong, you waste money. Our PSU calculator helps you find the right wattage for your exact build in just a few clicks.
Start by picking your CPU brand and model. Then choose your graphics card, RAM, storage drives, fans, and cooling setup. The calculator adds up the power draw from every part and includes a safety buffer so your PSU never runs at full load. You get a clear wattage recommendation, a power breakdown chart, and a cost estimate for electricity.
This tool works for all types of builds, from budget office PCs to high-end gaming rigs with multiple GPUs. It covers Intel and AMD processors, NVIDIA and AMD graphics cards, and Intel Arc GPUs. This calculator tells you exactly what PSU size you need for a first build or an upgrade.
How to Use Our PSU Calculator
Enter your PC parts below to find out how many watts your power supply needs. The calculator adds up the power draw of each part and tells you the right PSU size for your build.
CPU Brand: Pick Intel or AMD. This unlocks the rest of the calculator.
Socket Type: Choose the CPU socket that matches your motherboard.
CPU Model: Select your specific processor from the list. Each one shows its power draw in watts.
CPU Overclocking: Pick None if your CPU runs at stock speeds. Pick OC for light overclocking or Heavy for extreme overclocking.
Motherboard Form Factor: Choose the size of your motherboard, such as ATX or Mini-ITX. Bigger boards use more power.
GPU Configuration: Choose whether you have one or two graphics cards in your system.
GPU Manufacturer: Pick NVIDIA, AMD, or Intel for each graphics card slot.
GPU Model: Select your exact graphics card. Each one shows its TDP in watts.
GPU Overclocking: Set the overclock level for each GPU, just like the CPU option.
RAM Module: Choose your RAM type and size, such as DDR5 16GB or DDR4 8GB.
RAM Sticks: Enter how many RAM sticks are installed in your PC.
SSD / NVMe Drives: Enter the number of solid state drives in your build. Each one uses about 6 watts.
HDD Drives: Enter the number of hard disk drives. Each one uses about 9 watts.
Case/CPU Fans: Enter the total number of fans in your case. Each fan uses about 3 watts.
CPU Cooler: Pick your cooler type. Stock air coolers add no extra watts. Liquid coolers and custom loops add 15 to 25 watts.
RGB / Lighting: Choose how much RGB lighting your build has, from none to heavy.
Safety Headroom: This adds extra wattage so your PSU is never maxed out. A 30% buffer is a good starting point for most builds.
Click Calculate to see your recommended PSU wattage, a power breakdown chart, and a full parts table. Click Reset to clear all fields and start over.
What Is a PSU Calculator?
A PSU calculator helps you figure out how much power your computer needs. PSU stands for Power Supply Unit. It is the part inside your PC that sends electricity to every component, like your CPU, graphics card, RAM, and storage drives. If your PSU is too weak, your computer can crash, shut down, or not turn on at all. If it is too strong, you just spend extra money you did not need to.
Why PSU Wattage Matters
Every part in your computer uses a certain amount of power, measured in watts. A basic office PC might only need 300 watts, while a high-end gaming PC with a powerful graphics card could need 850 watts or more. When you add up the watts from every component, you get your total system load. Your power supply should always be rated higher than that total. A common practice is to add 20% to 30% extra headroom so your PSU is never running at full capacity. This keeps it cooler, quieter, and longer-lasting.
How to Pick the Right Power Supply
Start by knowing your two biggest power draws: the CPU and the GPU. These two parts alone often use more than half of your total power. After that, add in your motherboard, RAM sticks, hard drives, SSDs, fans, and any RGB lighting. Once you have the total, round up to the nearest standard PSU size, like 550W, 650W, 750W, or 850W. You should also look for a PSU with an 80 Plus rating. This rating tells you how efficiently the PSU converts wall power into usable power.1 Common ratings are 80+ Bronze, Gold, and Platinum. Higher ratings waste less electricity as heat, which saves you money on your electricity cost over time. If you want to convert between watts and amps to check your wall outlet capacity, our watts to amps calculator makes that easy.
Overclocking and Power Draw
Overclocking means pushing your CPU or GPU to run faster than its default speed. This gives you better performance, but it also uses more electricity. A heavily overclocked chip can draw 25 watts or more above its normal rating. If you plan to overclock, always pick a PSU with extra headroom to handle those power spikes safely. Understanding the relationship between voltage, current, and resistance is key to safe overclocking.