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. It looks like a string of letters and numbers — something like "SN1A2B3C4D5E" — and it's different from your device name or username. The location and how you retrieve it varies significantly between Windows, Mac, and Linux machines.

The fastest way is usually to check a physical label on your device itself. Most laptops have a sticker on the bottom or inside the battery compartment. Desktop computers often have the serial number on the back panel or inside the case. If you can't find a physical label or prefer to retrieve it digitally, your operating system stores this information and you can pull it up in seconds.

Key Takeaways

  • Your computer's serial number is a unique manufacturer identifier, different from your device name or password, and is often printed on a physical sticker underneath or inside your machine.
  • Windows users can find the serial number by opening Command Prompt and typing a single command, or by checking System Information in Settings.
  • Mac users can locate the serial number in System Report under the Apple menu, which also shows hardware details like processor and memory.
  • Linux users can retrieve the serial number using terminal commands like dmidecode or lshal, depending on their distribution and permissions.
  • You will need your serial number for warranty claims, hardware repairs, device registration, and tracking if your computer is stolen.

Finding the serial number on a Windows computer

The quickest digital method on Windows is to use Command Prompt. Press the Windows key, type "cmd" into the search box, and open Command Prompt (you do not need administrator access for this). Type the command wmic bios get serialnumber and press Enter. Your serial number will appear on the next line.

If you prefer to avoid the command line, you can find it in Settings instead. Open Settings, go to System, then select About. Scroll down to find "Device specifications" — your serial number may appear here as "System Serial Number" or "Device ID," though some manufacturers do not display it in this location. If it is not there, the Command Prompt method is more reliable.

For older Windows machines or if neither method works, check the physical device. Flip your laptop over and look for a sticker on the bottom panel. On desktop computers, open the side panel and look for a label on the motherboard or chassis. The serial number is usually printed in a format like "SN:" followed by the alphanumeric code.

Finding the serial number on a Mac

Click the Apple menu in the top-left corner and select About This Mac. A window will open showing your Mac's basic information. Click the System Report button. In the System Report window, look for "Serial Number" in the Hardware section — it appears near the top of the list, usually right after the model name and processor information.

The System Report also shows you other useful details like your Mac's processor, memory, and storage capacity. If you need to copy the serial number to paste it elsewhere, you can click on the serial number field and use Command+C to copy it. This method works on all modern macOS versions.

If you have an older Mac or the serial number does not appear in System Report, check the physical device. Look on the bottom of your MacBook or the back of your iMac for a small sticker with the serial number printed on it. Apple also engraves the serial number on some models, so check the edges and corners carefully.

Finding the serial number on a Linux computer

Linux does not have a single standard location for serial number information, so the method depends on your hardware and distribution. Open a terminal and try the command sudo dmidecode -s system-serial-number. This command requires administrator (sudo) access and works on most Linux systems with BIOS or UEFI firmware. The serial number will print on the next line.

If that command does not work or returns no output, try cat /sys/class/dmi/id/product_serial (without sudo). This reads the serial number directly from the system's hardware information files. Some systems may require sudo access for this command as well. If neither command returns a result, your hardware may not expose the serial number through these standard interfaces.

Another option is to check the physical device. Most Linux computers are either laptops or custom-built desktops. Laptops usually have a sticker on the bottom or inside the battery compartment. For custom-built desktops, the serial number may be on the motherboard itself, which you can see by opening the case — look for a label printed directly on the board or on a sticker attached to it.

Why you need your serial number and when to use it

Your serial number is required for several important situations. If your computer needs warranty service, the manufacturer will ask for it to verify coverage and access your service history. When you register your device with the manufacturer or with your insurance company, you will need the serial number to link the device to your account. If your computer is stolen and you report it to police or your insurance company, the serial number is the primary way to prove ownership and track the device.

You may also need it when selling your computer, as buyers often want to verify the device's history and authenticity. Some software licenses are tied to your hardware serial number, so you may need it when transferring licenses to a new machine. Keep a record of your serial number in a safe place — write it down or store it in a password manager — so you have it available if you ever need it.

Common mistakes when looking for your serial number

The most common mistake is confusing your serial number with other identifiers. Your device name (the name you gave your computer when you set it up) is not your serial number. Your username or email address is not your serial number. Your MAC address (a network identifier) is not your serial number. Your product key or license number is not your serial number. These are all different codes that serve different purposes.

Another mistake is assuming the serial number is always visible in Settings or System Information. Some manufacturers, particularly custom builders and some Linux systems, do not populate this field. If you cannot find it digitally, the physical sticker is your most reliable source. Do not assume a command failed just because it returned no output — try a different method before giving up.

Finally, do not confuse your serial number with your IMEI or ICCID if you are looking at a mobile device. Computers and phones use different identification systems. If you are looking at a laptop with a built-in cellular modem, it may have both a computer serial number and a cellular IMEI — make sure you are using the correct one for your purpose.

What to do if you cannot find your serial number

If you have tried the digital methods and checked the physical device without success, contact the manufacturer's support team. You will need to provide your device model and purchase information. They can look up your serial number in their system or help you locate it on your specific model. Keep your proof of purchase or warranty documentation handy when you contact them.

If your device is under warranty and you need the serial number for a claim, the manufacturer can often proceed without it if you can provide the model number, purchase date, and proof of purchase. However, having the serial number makes the process faster and more straightforward. If your device was custom-built by a local shop or builder, contact them directly — they may have records of your serial number from the build process.

Frequently Asked Questions

Is my serial number the same as my product key?

No. Your serial number is a unique identifier assigned by the hardware manufacturer to your specific device. Your product key is a code used to register or set up software (like Windows or Microsoft Office). They serve different purposes and are not interchangeable.

Can I change my computer's serial number?

On most systems, the serial number is stored in firmware or BIOS and cannot be changed through normal means. Attempting to modify it requires specialized tools and may void your warranty or violate terms of service. There is no legitimate reason to change your serial number.

What if my laptop sticker is worn off and I cannot read the serial number?

Use the digital method for your operating system (Command Prompt for Windows, System Report for Mac, or terminal commands for Linux). If the digital method does not work, contact the manufacturer with your model number and proof of purchase — they can retrieve your serial number from their records.

Do I need my serial number to sell my computer?

Many buyers will ask for it to verify the device's authenticity and check its history. Having it available speeds up the sale process. If you cannot provide it, some buyers may be hesitant or offer a lower price due to the inability to verify ownership history.

Where is the serial number on a desktop computer?

Desktop serial numbers are usually on a sticker on the back panel or inside the case on the motherboard or chassis. Some manufacturers print it on the power supply or front bezel. Check all exterior surfaces first, then open the side panel if needed. The digital methods (Command Prompt for Windows, System Report for Mac) also work on desktops.