Computer PSU Wattage Calculator: Estimate Power Needs
Computer PSU Wattage Calculator estimates the total power draw of your selected parts and recommends a power supply size with extra capacity. Add your components to plan a new build or upgrade.
How to Use the Tool
- Choose how you use the PC. Enter the electricity price from your power bill.
- Select your processor. Choose a graphics card or select integrated graphics.
- Add the rest of your parts. Include extra cards and powered USB devices.
- Enter your current PSU capacity if you want to compare it with the result.
- Select Calculate Recommended Wattage to see the result and energy estimate.
Details to Have Ready
- The exact CPU model
- The exact graphics card model and card count
- The RAM type and number of modules
- The number of storage drives
- The cooling setup and case fan count
- Any expansion cards or powered USB devices
If a CPU or graphics card is missing, choose Other / Enter Wattage. Use the power value from the maker's page for your exact part.
If you are unsure about a part name, check its product page. You can also use our hardware lookup tool.
How the Estimate Works
The tool adds a planning value for each selected part. Your usage profile changes the safety buffer. The final number is rounded up to a PSU size supported by the tool.
Current Intel values use Maximum Turbo Power when it is listed in Intel Product Specifications. Older Intel entries use thermal design power (TDP). AMD entries use Default TDP from the AMD processor database. These limits are different, so the result is a planning estimate.
Graphics values use published board-power figures. Sources include the NVIDIA comparison page and the AMD product database. Intel provides separate Arc graphics specifications.
The overclock choice adds a broad adjustment to the CPU value. It does not measure the settings on your PC.
Understanding Your Result
Recommended Wattage
The large result is the suggested PSU capacity. It is not a claim that your PC will draw that amount all the time. The breakdown shows how the tool reached the total.
Energy Use and Cost
The energy section uses your entered rate and daily hours. It also uses a broad load estimate for the selected workload. It cannot predict a power bill.
Electricity prices vary by place and customer type. The U.S. Energy Information Administration publishes current national data. Your own bill is the best source for the rate to enter.
Efficiency Rating
The 80 Plus program tests PSU efficiency at set load levels. Its rating does not replace checks for wattage and cable support. Use the result as one part of your buying decision.
Checks Before You Buy
Check the Case
The motherboard choice helps estimate base power. It does not tell the tool which PSU size fits your case. Check the case manual for its supported power supply sizes. Intel documents the main PSU standards in its ATX design guide.
Check the Power Cables
Connector needs can vary within one graphics card family. NVIDIA tells buyers to check the exact card maker's specifications in its RTX 4060 guide. Intel gives the same advice in its Arc setup guide. Compare the card requirements with the cables included with the PSU.
Partner cards may use different power limits or plugs. Review the product page for the exact card before placing an order. Also check the PSU maker's cable list and warranty terms.
After choosing a power supply, enter the estimated draw in our gaming PC UPS size calculator to plan battery backup power.