How to Check Power Supply Wattage in Windows 11

Windows 11 cannot show the wattage of a desktop PC’s power supply, because a standard power supply unit (PSU) does not report its rating to the operating system. To find it, shut down and unplug the PC, remove the case side panel, and read the total watts (W) printed on the label on the side of the power supply. On a prebuilt PC you can often skip opening the case by looking up the model on the manufacturer’s support site, and on a laptop the wattage is printed on the charger.

Applies to: Windows 11 desktop PCs and laptops (the label and lookup methods are the same on Windows 10). Checked against Microsoft Support on October 7, 2026.

Why Windows 11 cannot tell you the wattage

Parts such as the processor, graphics card and drives identify themselves to Windows, which is why you can see them in Settings, Task Manager and System Information. A typical desktop power supply has no data connection of that kind. It only delivers power, so Windows has nothing to read. Microsoft’s own tools reflect this: the System Information tool is documented as showing hardware, system components and the software environment, and the battery classes Windows exposes describe a battery, not an AC power supply.

This also means that commands and apps claiming to print your PSU wattage are showing something else, usually battery data on a laptop or an estimate of how much power the parts are using right now. Use the table below to pick the method that fits your computer.

Your computer	Best way to find the wattage	Do you open the case?
Custom-built or upgraded desktop	Read the label on the power supply	Yes (side panel only)
Prebuilt desktop that has never been repaired or upgraded	Look up the model or serial number on the manufacturer’s support site, or read the label	No for the lookup
Laptop, mini PC or all-in-one with an external adapter	Read the output rating printed on the adapter	No

Before you start

• Know what you are looking for. The rating is a number followed by W, such as 450W, 650W or 850W. It is the most power the unit is built to deliver, not what your PC is drawing at the moment.
• Check your warranty. If the PC is still under warranty, read the manufacturer’s instructions for opening the case first. If you are not comfortable opening it, use the lookup method further down or ask a repair shop.
• Have a light and a phone ready. The label is often in a dark corner, and a photo is easier to read than the sticker itself.

Read the wattage from the power supply label

This is the only method that tells you for certain which power supply is in the PC today.

1. Shut down the PC. Use a full shutdown rather than sleep, and wait until the fans and lights are off.
2. Switch off the power supply and unplug it. If there is a rocker switch next to the power socket on the back of the PC, set it to off, then pull the power cord out of the PC.
3. Remove the case side panel. Follow your PC or case manufacturer’s instructions. Touch a bare metal part of the case before reaching inside so you do not pass static electricity to the components.
4. Find the power supply. It is the metal box that the power cord plugs into, with bundles of cables running from it to the motherboard, graphics card and drives.
5. Read the label. Look for the large sticker on the side or top of the unit. Note the total wattage and the model number. If the sticker faces the far side of the case, you may need to remove the other panel as well. You should not need to unscrew the power supply.
6. Take a photo, then close the case. Refit the panel, plug the cord back in, turn the rocker switch on and start the PC. Nothing in Windows changes, so there is nothing to undo.

Warning: never open the metal enclosure of the power supply itself. The parts inside can hold a dangerous electrical charge even after the PC is unplugged. Everything you need is printed on the outside.

How to read the label

A power supply label carries more than one number, so it helps to know which one answers your question.

• Total wattage. This is usually the largest number on the sticker and is often part of the model name. Intel’s power supply guidance separates continuous power, which the unit is designed to deliver all the time, from peak power, which it can only deliver for short periods. If both appear, the continuous figure is the one to use.
• Model or part number. Search for it on the power supply maker’s website to see the full specifications and the cables the unit supports. Corsair, for example, prints a part number that starts with CP on the side or top of its power supplies.
• The voltage table. The rows of volts (V) and amps (A) show how the total is divided among the different outputs. Watts are volts multiplied by amps, which is how you can work out the power available on a single output.
• 80 PLUS badge. A badge such as 80 PLUS Bronze or Gold describes efficiency, meaning how much of the power drawn from the wall reaches the PC. It does not tell you the wattage. A 500W Gold unit and a 500W Bronze unit supply the same maximum power.

Look up a prebuilt PC without opening it

If your desktop came from Dell, HP, Lenovo or another large manufacturer and still has its original parts, the manufacturer’s records can tell you the wattage.

1. Find the exact model name and the serial number or service tag. They are printed on a sticker on the back, top or underside of the case.
2. Go to the manufacturer’s official support website and enter that number.
3. Open the product specifications or the original configuration (parts list) for your PC and look for the power supply entry.

Many models are sold with more than one power supply option, so a specification sheet for the model line may list two or three wattages. The serial-number lookup or the label settles which one you have. If the PC was bought used or has been repaired, the power supply may have been swapped, so check the label. Windows can help with the other parts: our guide to checking your PC specs in Windows 11 shows where to find the processor and graphics card names you will need for an upgrade.

Check a laptop charger’s wattage

A laptop does not have an internal power supply of the desktop kind. Its power comes from the external adapter, and the rating is printed on that adapter.

1. Unplug the adapter and find the small print on the brick or plug.
2. Look for the line marked output. Many adapters state the watts directly, for example 65W.
3. If only volts and amps are listed, multiply them. An output of 20V and 3.25A is 65W.

USB-C chargers often list several output lines because they can supply different voltages. The highest volts-times-amps pair is the charger’s maximum. When replacing a charger, match the wattage the laptop maker specifies for your model.

What Windows 11 tools actually show

These built-in tools are useful, but none of them reports a power supply’s rated wattage.

• Task Manager. Press Ctrl + Shift + Esc to open it. The Processes and Performance tabs show which apps and components are working hardest. That tells you about demand, not about the capacity of the power supply.
• System Information. Press Windows logo key + R to open the Run dialog box, type msinfo32 and press Enter. You get a detailed view of the hardware and software, starting at System Summary, but there is no power supply wattage entry.
• Battery report (laptops). Select Start, type Command prompt, right-click it and choose Run as administrator, then type powercfg /batteryreport and press Enter. Windows saves an HTML report and shows its location. The report covers the installed battery and its usage. Battery capacity is measured in milliwatt-hours (mWh), which is stored energy, so it is not the charger’s wattage. See how to check battery health in Windows 11 for a walkthrough of that report.
• Energy report. Microsoft documents powercfg /energy as a command that analyzes the system for common energy-efficiency and battery-life problems over 60 seconds by default. It does not identify the power supply.

Microsoft lists every option for these commands in its powercfg command-line reference, and the battery report steps are in Caring for your battery in Windows.

Third-party hardware-monitoring apps and plug-in wall power meters work the same way: they estimate or measure how much power the PC is using at that moment. That is helpful for judging how close you are to the limit once you know the rating, but it is never the rating itself.

Is your wattage enough for an upgrade?

Most people check the wattage because they want a new graphics card. Once you have the number from the label, compare it with the card maker’s stated requirement rather than guessing.

• Check the card’s required system power. NVIDIA, for example, lists a required system power of 650 W for the GeForce RTX 5070 and 750 W for the RTX 5070 Ti on its RTX 5070 family specifications, and notes that requirements can differ depending on the rest of the system.
• Check the connectors. The same NVIDIA page calls for two PCIe 8-pin cables (with the adapter in the box) or a single PCIe Gen 5 cable rated for 300 W or more. A power supply with enough watts but without the right cables still will not work.
• Leave some headroom. Intel’s guidance gives the example of a system calculated to use 500 watts being a good match for a 600 or 650-watt power supply. A power supply only delivers what the PC asks for, so a larger unit does not use more electricity by itself.
• Use a manufacturer calculator for a full build. Tools such as Corsair’s PSU calculator add up the processor and graphics card requirements and then allow extra for the other parts.
• Do not reuse cables between power supplies. Intel’s guidance warns against mixing and matching modular cables from other manufacturers, so use the cables that came with the unit.

Troubleshooting

The label is missing, worn or hidden

Some cases have a cover (shroud) over the power supply. Check the opposite side panel first. If the sticker is unreadable, look for a model or part number stamped elsewhere on the unit and search for it on the maker’s website. On a prebuilt PC, use the serial-number lookup instead.

The label shows several wattage numbers

Use the total or maximum continuous output. Smaller figures next to individual voltages are limits for those outputs, not the overall rating.

An app or command shows a wattage that does not match the label

Trust the label. Software figures are live power draw or estimates, and on a desktop they are often incomplete because the power supply is not reporting anything.

You cannot open the case

Slim business desktops, all-in-ones and PCs with warranty seals may not be meant to be opened by the owner. Use the manufacturer’s support site, or contact the manufacturer with the serial number. On a work or school PC, ask your IT department rather than opening the hardware.

The PC shuts off under load after an upgrade

Sudden power-offs or restarts during games right after adding a graphics card can point to a power supply that is too small or is missing a required cable. Compare the label with the card maker’s required system power and confirm every power connector on the card is fully seated.

Frequently asked questions

Can I check my power supply wattage without opening the PC?

Only indirectly. On a prebuilt PC, the manufacturer’s support site can show the original power supply for your serial number, and your order confirmation or the power supply’s box will list it for a custom build. Some cases have a window or mesh panel that lets you read the label with a flashlight. No Windows 11 setting or command shows it.

Is there a Command Prompt or PowerShell command for PSU wattage?

No. Commands that are sometimes suggested for this return battery information on laptops or nothing useful on desktops. Microsoft’s powercfg reference includes battery and energy reports, but nothing that reads a power supply’s rating.

Does Task Manager show how many watts my PC uses?

No. Task Manager shows how busy the processor, memory, disk and graphics card are. To measure actual power draw you need a wall power meter, and that still measures use, not the power supply’s capacity.

Does a higher-wattage power supply use more electricity?

Not by itself. The PC draws what its parts need. A 750W unit in a PC that needs 400 watts supplies about 400 watts. Efficiency, shown by the 80 PLUS level, determines how much extra is lost as heat.

Can the BIOS or UEFI show the power supply wattage?

No, for the same reason Windows cannot: a standard power supply does not report its rating to the motherboard. Any power or voltage figures you see in firmware are live sensor readings, not the rated wattage.

How do I know which power supply to buy as a replacement?

Match three things: enough wattage for your parts with some headroom, the physical size (form factor) your case accepts, and the connectors your motherboard and graphics card need. Prebuilt PCs sometimes use non-standard sizes or connectors, so check the manufacturer’s documentation before ordering.

Once you have the wattage and model number from the label, keep the photo with your PC’s records. Before buying a new graphics card, compare that number with the card maker’s required system power and check that your power supply has the cables the card needs.