Where to find your serial number on Windows

Your laptop's serial number is a unique identifier printed or etched on the device itself, and Windows stores it in your system information. The fastest way to find it is to open the Run dialog by pressing Windows key + R, type msinfo32, and press Enter. A window titled "System Information" will open. Look for the field labeled "System Serial Number" — this is your laptop's unique identifier.

If that method does not work, you can reach the same information through Settings. Open Settings, go to System, then select About. Scroll down until you see "Device specifications" and look for "System serial number" in that section. Both paths lead to the same number, so use whichever feels more natural to you.

Write down or screenshot the number exactly as it appears. Serial numbers are case-sensitive and often contain both letters and numbers, so accuracy matters if you need to reference it later for warranty claims or technical support.

Where to find your serial number on Mac

On a Mac, the serial number lives in the system information menu. Click the Apple menu in the top-left corner, select About This Mac, and a window will appear. The serial number is listed as "Serial Number (system)" near the top of the Overview tab. You can also find it under System Report if you click that button — it will be labeled the same way.

An alternative method is to hold Option and click the System Information icon in Applications > Utilities. This opens the same window directly. Either approach takes about 10 seconds and requires no special access or passwords.

Finding the serial number printed on your device

Every laptop also has a physical serial number printed or engraved somewhere on the hardware itself. On most Windows laptops, this is on the bottom of the device — flip your laptop over and look for a sticker or engraved text. The serial number is usually a string of 8 to 12 characters and may be labeled "S/N", "Serial No.", or "Service Tag".

On a Mac, the serial number is typically on the bottom of the device as well, though some models print it on the battery or inside the battery compartment. If your laptop is very new or has been replaced under warranty, the physical number should match the one in your system information. If they do not match, contact the manufacturer — it may indicate a hardware swap or refurbished unit.

The physical serial number is useful when you cannot turn on your laptop or when you need to reference it before the device boots. Keep a photo of it in your phone or email for situations where you need it but do not have the laptop with you.

Why you might need your serial number

Manufacturers and support teams use serial numbers to look up your warranty status, service history, and what repairs or replacements have been done on your device. If you contact technical support, they will often ask for this number before they can help you. It is also required when you file an insurance claim for a lost or damaged laptop.

Some software licenses are tied to your device's serial number rather than to your account, so you may need it when you move software to a new computer or when you reinstall an operating system. Retailers sometimes ask for it when you purchase extended warranties or accidental damage coverage.

What to do if you cannot find your serial number

If your laptop will not turn on and you cannot access the system information menu, the physical serial number on the bottom or back of the device is your only option. Take a clear photo of it with your phone and send it to the manufacturer's support team.

If the physical sticker is worn, faded, or missing, contact the manufacturer directly with your proof of purchase. They can often look up your device using your purchase receipt, the device's MAC address (a different identifier found in network settings), or your account information if you registered the laptop when you bought it.

Key Takeaways

  • On Windows, press Windows key + R, type msinfo32, and look for "System Serial Number" in the window that opens.
  • On Mac, click the Apple menu, select About This Mac, and the serial number appears at the top of the Overview tab.
  • Your laptop also has a physical serial number printed on the bottom or back of the device, which you can reference if the computer will not turn on.
  • Manufacturers use your serial number to check warranty status, service history, and to help with technical support or insurance claims.
  • If you cannot find your serial number, contact the manufacturer with your proof of purchase and they can look it up for you.

Frequently Asked Questions

Is my serial number the same as my product key or license code?

No. Your serial number identifies the physical device itself. A product key or license code identifies your software or subscription. They are completely separate. You need the serial number for hardware support and warranty claims; you need the product key for software installation or account recovery.

Can someone use my serial number to access my laptop remotely?

No. Your serial number is a hardware identifier, not a password or access credential. It is safe to share with manufacturers, support teams, or insurance companies. It does not grant anyone access to your files, accounts, or network.

What if the serial number in my system information does not match the one on the bottom of my laptop?

This usually means the device has been refurbished, repaired, or had its motherboard replaced. Contact the manufacturer with both numbers and your proof of purchase. They can confirm whether the device is legitimate and what work has been done on it.

Do I need my serial number to sell my used laptop?

It is helpful to provide it to the buyer so they can verify the device is not stolen and check its warranty status. Some buyers will ask for it. You should also note it yourself before you sell, in case you need to reference it later for your own records.