Where to find your serial number depends on your operating system

Your computer's serial number is a unique identifier printed or encoded by the manufacturer. On Windows, you can find it through the System Information tool. On Mac, it lives in the About This Mac menu. On Linux, the location varies by distribution, but the dmidecode command usually retrieves it. The serial number is not the same as your product key or license number — it identifies the physical machine itself, not the software running on it.

You may need your serial number for warranty claims, repairs, insurance documentation, or IT asset tracking. Knowing where to look takes less than a minute, and you do not need administrator access on most systems.

Key Takeaways

  • On Windows, open System Information by typing "msinfo32" in the Run dialog and look for "System Serial Number" in the main window.
  • On Mac, click the Apple menu, select About This Mac, and find the serial number listed under System Report.
  • On Linux, run the command sudo dmidecode -s system-serial-number in the terminal to display your serial number.
  • Your serial number is printed on a sticker on the physical computer chassis, usually on the back or bottom, if you prefer not to use software.
  • The serial number is different from your product key, MAC address, or device name — each serves a different purpose.

Finding the serial number on Windows

The quickest method on Windows is the System Information utility. Press Windows key + R to open the Run dialog, type msinfo32, and press Enter. The System Information window opens when ready. Look for the field labeled System Serial Number in the main list — it appears near the top, usually after System Manufacturer and System Model. Copy or write down the alphanumeric code shown next to it.

If you prefer using Settings instead, open Settings, go to System, then About. Scroll down to find Device specifications. The serial number may appear here as well, though the label varies by Windows version. Some older Windows machines do not display the serial number in Settings, so System Information is the more reliable route.

If neither method shows a serial number, your computer may not have one stored in the BIOS or firmware — this is rare but happens on some custom-built machines. In that case, check the physical sticker on the back or bottom of the chassis.

Finding the serial number on Mac

On any Mac, click the Apple menu in the top-left corner and select About This Mac. A window opens showing your Mac model, processor, memory, and other details. Look for the field labeled Serial Number — it appears in the main overview tab. The serial number is typically a mix of letters and numbers, usually 11 to 12 characters long on modern Macs.

If you need more detailed hardware information, click the System Report button in the same window. This opens a more detailed view where the serial number also appears near the top under Hardware Overview. Both locations show the same number, so use whichever is easier for you to access.

Finding the serial number on Linux

Linux systems store hardware information in the BIOS or firmware, accessible through the dmidecode command. Open a terminal and type the following command:

sudo dmidecode -s system-serial-number

Press Enter and provide your password when prompted. The serial number displays on the next line. If the command returns nothing or an error, your system may not have a serial number stored in the firmware — this is more common on older machines or virtual machines. Some Linux distributions also allow you to check /sys/class/dmi/id/product_serial by running cat /sys/class/dmi/id/product_serial, though this requires root access and does not work on all systems.

Checking the physical sticker on your computer

Every computer has a manufacturer's sticker with the serial number printed on it. On laptops, this sticker is usually on the bottom of the chassis or sometimes on the back panel. On desktop computers, check the back panel, the side of the tower, or underneath. The sticker typically shows the manufacturer name, model number, and a barcode alongside the serial number.

The physical sticker is useful if your computer will not start, if the operating system is corrupted, or if you straightforward prefer not to boot into the system. The serial number on the sticker matches the one stored in the firmware, so either source is equally valid for warranty or repair purposes.

What your serial number is used for

Manufacturers use serial numbers to track individual units through production, warranty registration, and repair history. If you need to file a warranty claim, the manufacturer will ask for your serial number to look up your purchase date and coverage terms. Repair shops use it to order replacement parts specific to your model and to document service history.

Insurance companies may ask for your serial number when you file a claim for theft or damage. IT departments in workplaces use serial numbers to track company-owned equipment and manage asset inventories. If you sell or donate your computer, providing the serial number to the new owner helps them register it with the manufacturer if needed.

Serial number versus other identifiers

Your serial number is not the same as your product key, MAC address, or device name, and mixing them up can cause confusion. Your product key (or license key) is a code that proves you own a copy of Windows, Office, or other software — it is not tied to your specific computer. Your MAC address is a network identifier used by your ethernet or Wi-Fi card to communicate on a local network; every network device has one, and it can be changed. Your device name (or hostname) is a label you assign to your computer for identification on a network; you can change it anytime.

Your serial number, by contrast, is assigned by the manufacturer and never changes. It identifies the physical hardware itself, not the software or network settings. When a technician asks for your serial number, they are asking for the hardware identifier, not any of these other codes.

Frequently Asked Questions

Can I change my computer's serial number?

On most consumer computers, the serial number is stored in the firmware or BIOS and cannot be changed without specialized tools. Changing it is not recommended and may void your warranty. If you need to update your computer's registered information, contact the manufacturer directly with proof of ownership.

What if my computer does not have a serial number?

Custom-built desktop computers and some older machines may not have a serial number stored in the firmware. In this case, check the physical sticker on the chassis. If no sticker exists, you can use your MAC address or device name as an alternative identifier for your own records, though manufacturers will not recognize these as official serial numbers.

Is my serial number the same as my product key?

No. Your serial number identifies the physical computer hardware. Your product key identifies your license to use Windows or other software. They are completely separate. You need the serial number for hardware warranty or repair; you need the product key to reinstall or set up Windows.

Do I need the serial number to sell my computer?

It is helpful to provide the serial number to the buyer so they can register the computer with the manufacturer if they choose. However, it is not required. Make sure to wipe your personal data before selling, and consider deactivating any software licenses tied to the machine.

Where is the serial number on a laptop versus a desktop?

On laptops, the sticker is usually on the bottom or back. On desktops, it is typically on the back panel or side of the tower. Both can also be found through System Information (Windows), About This Mac (Mac), or dmidecode (Linux) without opening the computer.