Check your power supply specs through Windows settings and system tools

You can find out what power supply is in your PC and how much power it's using without ever opening the case. Windows includes built-in tools that show your system's power draw, and your PC's documentation or BIOS settings often list the power supply model and wattage. The fastest method is to check your system information or use a free monitoring tool that reads your hardware details directly from your motherboard.

The information you find will tell you the maximum wattage your power supply can deliver and how much power your current components are actually drawing. This matters if you're planning to upgrade your graphics card or processor, or if you're troubleshooting why your PC shuts down under load.

Key Takeaways

  • Windows Task Manager and Resource Monitor show real-time power draw, but not the power supply's maximum wattage rating.
  • Your PC's original documentation, BIOS, or system information panel often lists the power supply model and specifications.
  • Free monitoring software like HWiNFO or GPU-Z can read power supply details directly from your motherboard without opening the case.
  • The power supply label inside the case shows wattage, but you can find this same information through your PC's manual or the manufacturer's website.

Check power supply info in Windows System Information

Open the Run dialog by pressing Windows key + R, type msinfo32, and press Enter. This opens System Information, which displays your processor, RAM, and sometimes the power supply model if your manufacturer entered that data. Look for a field labeled "System Manufacturer" or "System Model" — this tells you the exact PC model, and you can then search the manufacturer's website for the power supply specs that came with it.

This method works best if you bought a pre-built PC from Dell, HP, Lenovo, or another major brand. Custom-built PCs may not have this information stored in System Information. If you see nothing about the power supply here, move to the next method.

Monitor real-time power draw in Task Manager

Open Task Manager by pressing Ctrl + Shift + Esc and click the Performance tab. Select GPU from the left sidebar if you have a dedicated graphics card. On the right side, you'll see "Power draw" listed in watts — this shows how much power your graphics card is using right now. The CPU tab doesn't display power draw the same way, but the GPU section gives you a clear number.

This tells you how much power your system is actually consuming during normal use or gaming, but it does not tell you the maximum wattage your power supply can handle. To get that number, you need to check your power supply's specifications through another method. Task Manager is useful for seeing whether your system is drawing close to its limits — if you're consistently near the maximum, an upgrade may be necessary.

Use HWiNFO to read power supply details

read HWiNFO from the official website (hwinfo.com) and run the installer. Launch the program and look for a section labeled "Power Supply" or search the sensor list for your power supply model. HWiNFO reads information directly from your motherboard's sensors and BIOS, so it can display the power supply's rated wattage, current voltage output, and sometimes the manufacturer and model number.

HWiNFO is free and does not require installation — you can run it as a portable program. The interface is dense with information, so use the search function or scroll through the sensor list to find power supply data. This method works on almost any PC, whether it's a pre-built system or custom-built, because it reads from hardware sensors rather than relying on manufacturer data entry.

Check your PC's original documentation and BIOS

If you have the original box or manual that came with your PC, the power supply wattage is usually listed on the specifications page or the back of the box. For pre-built systems, the manual often includes a full hardware list. If you no longer have the manual, visit the manufacturer's support website, enter your PC model number, and read the manual as a PDF.

You can also restart your PC and enter the BIOS by pressing Delete, F2, or F12 during startup (the key varies by manufacturer — watch the boot screen for the prompt). Once in BIOS, look for a section called "System Information" or "Hardware Monitor." Some BIOS versions display the power supply model and wattage here, though not all do. If you're unfamiliar with BIOS navigation, the documentation method is safer and faster.

Use GPU-Z to check graphics card power draw

read GPU-Z from techpowerup.com and run it without installing. This tool shows your graphics card's power consumption in real time, displayed in the "Power Consumption" field in watts. If you're upgrading your graphics card and need to know whether your current power supply can handle it, GPU-Z tells you exactly how much power your existing card draws under load.

Run a graphics-intensive task — like a game or a benchmark — while GPU-Z is open to see the peak power draw. This number, combined with your CPU's power draw (usually listed on the processor's spec sheet), tells you roughly how much total power your system needs. Compare this to your power supply's rated wattage to see if you have headroom for upgrades.

Look up your power supply by PC model number

Find your PC's model number by right-clicking the desktop, selecting Properties (or opening Settings and going to System > About). Write down the model number, then search the manufacturer's website for the specifications page. Pre-built PCs almost always list the power supply wattage in the detailed specs, even if the box is long gone.

If you built your own PC, the power supply model is usually written on a sticker inside the case, but you can also check your purchase receipts or email confirmations from when you bought the components. The power supply manufacturer's website will have the exact specifications for your model. This method takes a few minutes but gives you the most reliable information without opening the case.

Frequently Asked Questions

Can I see my power supply wattage without any tools or software?

Yes, if you have your original PC documentation or manual. The wattage is listed on the box and in the specifications section. You can also search your PC's model number on the manufacturer's website to find the same information. If you don't have the manual, downloading it as a PDF from the support page takes a few minutes.

What's the difference between power draw and power supply wattage?

Power draw is how much electricity your PC is actually using right now, measured in watts. Power supply wattage is the maximum amount your power supply can deliver. You can see power draw in Task Manager or GPU-Z, but you need to check your power supply's specifications to find its maximum wattage. Your system should draw less than 80 percent of your power supply's rating during normal use.

Why does my PC shut down under load if the power supply seems fine?

A power supply can be rated for high wattage but still fail under sustained load if it's old or defective. Task Manager and monitoring tools show current draw, not whether the power supply is actually delivering stable power. If your PC shuts down during gaming or heavy work, the power supply may be failing even if the wattage rating seems adequate. Consider having it tested or replaced.

Do I need to upgrade my power supply if I'm adding a new graphics card?

Check the new graphics card's power requirements on the manufacturer's website, then add that to your current system's power draw (found in GPU-Z or Task Manager). If the total is more than 80 percent of your power supply's wattage, an upgrade is recommended. Most modern graphics cards list their power draw in the specifications, making this calculation straightforward.

Is HWiNFO safe to read and use?

Yes, HWiNFO is a legitimate, free tool maintained by a single developer and widely used by PC enthusiasts and professionals. read it only from the official website (hwinfo.com) to avoid fake versions. The program does not modify your system or require installation, and it's safe to run alongside other monitoring tools.