Where to find your serial number in Windows

Your PC's serial number is stored in Windows itself, and you can pull it without opening your machine or hunting through paperwork. The fastest way is to open the Command Prompt and run a single command that reads the number directly from your system. On most Windows machines, this takes under a minute.

Windows keeps the serial number — also called the Service Tag or System Serial Number — in a location that the operating system can access when ready. Different manufacturers store it slightly differently, but Windows has a standard way to retrieve it that works across Dell, HP, Lenovo, ASUS, and most other brands.

Key Takeaways

  • Open Command Prompt as administrator and type wmic bios get serialnumber to see your serial number in seconds.
  • If Command Prompt does not work, check the System Information window by pressing Windows key + Pause/Break, or search "System Information" in the Start menu.
  • Your serial number may also be printed on a sticker on the back or bottom of your PC tower or laptop.
  • Some manufacturers print the serial number on the inside of the case or battery compartment, visible only when you open the machine.
  • Write down your serial number and store it somewhere safe — you will need it for warranty claims and tech support.

Using Command Prompt to retrieve your serial number

Open the Start menu and type Command Prompt. Right-click on "Command Prompt" and select "Run as administrator." A black window will open.

Type the following exactly as written and press Enter:

wmic bios get serialnumber

The serial number will appear on the next line. It is usually a string of letters and numbers — for example, ABC123XYZ456 or CN-0ABC123-12345. Copy this number and paste it into a document or email if you need to send it to support.

If you see an error message or the command does not return a number, your system may have restrictions on running WMI commands. Move to the System Information method instead.

Finding the serial number in System Information

Press the Windows key and Pause/Break at the same time. This opens the System window directly. Look for "System" in the left sidebar and click it if it is not already selected.

Scroll down to find "System SKU" or look for a field labeled "Serial Number" or "Service Tag." The exact label depends on your manufacturer, but the number will be visible in this window. If you do not see it here, try the next method.

Alternatively, press Windows key + R, type msinfo32, and press Enter. This opens System Information in full detail. Search the page for "Serial Number" or "System SKU" using Ctrl + F.

Checking the physical sticker on your PC

Most manufacturers print the serial number on a label somewhere on the outside of your machine. On a desktop tower, check the back panel and the bottom. On a laptop, look on the underside of the device or on the battery compartment if the battery is removable.

The sticker usually includes the model number, serial number, and sometimes a barcode. The serial number may be labeled as "Serial Number," "Service Tag," "System Serial Number," or just "S/N." Write down the exact string of characters.

If the sticker is worn or missing, the Command Prompt or System Information method will still work. Do not assume the number is gone just because you cannot see it printed anywhere.

What to do if you cannot find the serial number

If Command Prompt returns nothing and System Information does not show a serial number, your PC may not have one stored in the standard location. This is rare but can happen with older machines, custom-built PCs, or systems with certain BIOS configurations.

Try opening Device Manager by right-clicking the Start button and selecting "Device Manager." Look for your hard drive or motherboard in the list, right-click it, select "Properties," and check the "Details" tab. Some manufacturers store the serial number in the device properties instead of the system BIOS.

If you still cannot locate it, contact the manufacturer's support line with your model number. They can often look up the serial number using your purchase date and the store where you bought it.

Why you need your serial number

Your serial number is required for warranty claims, repair requests, and technical support. When you contact a manufacturer or repair shop, they will ask for it to pull up your machine's history and coverage details. Having it on hand saves time and prevents delays.

Keep a record of your serial number in a safe place — a document on your computer, a note in your phone, or written on a piece of paper stored with your purchase receipt. If your PC is stolen or lost, the serial number helps law enforcement and the manufacturer identify it.

Frequently Asked Questions

Is the serial number the same as the product key?

No. The serial number identifies your specific machine. The product key is a code that proves you own a license to Windows or other software. You need both for warranty and software support, but they are different numbers.

Can I find the serial number if Windows will not start?

Yes. Check the physical sticker on your PC first — that is the fastest way if Windows is not running. If you need the number from the system itself, you will need to boot into the BIOS or use a bootable Linux drive to access the hardware information, which requires more technical steps.

Does every PC have a serial number?

Most factory-built PCs from major manufacturers have one. Custom-built or assembled PCs may not have a single serial number for the whole machine, though individual components like the motherboard or hard drive will have their own. Check your receipt to see what the manufacturer assigned.

What if the serial number on the sticker does not match the one in Windows?

This is unusual but can happen if the hard drive or motherboard was replaced. The number in Windows is usually more current. If you are filing a warranty claim, provide both numbers and explain the discrepancy to support — they can verify which one is correct in their system.