The fastest way depends on your operating system

Your laptop's serial number is usually printed on a sticker on the bottom or back of the machine, but you can also find it through your operating system settings if the sticker is worn or missing. Windows stores it in System Information, while Mac keeps it in About This Mac. The physical sticker is fastest if you can read it clearly — no login required, no menus to navigate.

If the sticker is damaged or you need the number right now without opening the laptop, you can also check your original purchase receipt, warranty card, or the box it came in. Many manufacturers print the serial number in multiple places for this reason.

Key Takeaways

  • The serial number is usually a sticker on the bottom or back of your laptop, printed clearly in a format like 12 characters or more depending on the brand.
  • On Windows, open System Information by pressing Windows key + R, typing msinfo32, and looking for the "Serial Number" field.
  • On Mac, click the Apple menu, select About This Mac, and find the "Serial Number" listed in the Overview tab.
  • If you cannot read the physical sticker or access your operating system, check your purchase receipt, warranty paperwork, or original packaging.
  • Different manufacturers format serial numbers differently — some use letters and numbers, others use only numbers, and the length varies by brand.

Finding the serial number on the physical laptop

The easiest place to look is the bottom of your laptop. Flip it over and look for a white or silver sticker with text printed on it. Most manufacturers — Dell, HP, Lenovo, ASUS, and others — print the serial number prominently on this sticker, usually labeled as "Serial Number," "S/N," or "Service Tag." The sticker may also include the model number, product code, and other information, but the serial number is typically the longest string of characters.

If the bottom sticker is worn or missing, check the back panel near the hinge, the side edges, or under the battery (if your laptop has a removable battery). Some older models also print it on the inside of the screen bezel or on the keyboard surround. Take a photo of the sticker with your phone if the text is hard to read — you can zoom in on the photo later.

Finding the serial number in Windows settings

To find your serial number through Windows without opening the laptop case, press the Windows key and R at the same time to open the Run dialog. Type msinfo32 and press Enter. This opens System Information, a built-in Windows tool that displays hardware details.

In the System Information window, look at the list on the left side under "System Summary." Scroll down until you see "Serial Number" — the value next to it is your laptop's serial number. This method works on Windows 10 and Windows 11. If you do not see a Serial Number field, your laptop manufacturer may not have stored it in this location, and you should check the physical sticker instead.

Finding the serial number on a Mac

On a Mac, click the Apple menu in the top-left corner of the screen and select About This Mac. A window opens showing your Mac's basic information. In the Overview tab, look for "Serial Number" — it appears as a code like "C02ABC1D2EFG" or similar. You can click the serial number to copy it to your clipboard if you need to paste it elsewhere.

If you do not see the serial number in About This Mac, your Mac may be very old or the information may not be stored there. In that case, check the physical sticker on the bottom or back of the machine, or look at your original purchase paperwork.

Checking your purchase records and packaging

If you still have your original laptop box, the serial number is often printed on the outside or inside of the packaging. Check the side panels and the bottom of the box first — manufacturers typically print key information in multiple locations. The serial number may also appear on any included documentation, such as a quick-start guide or warranty card.

Your purchase receipt from the retailer or manufacturer website may also list the serial number, especially if you bought the laptop directly from the maker. Check your email for order confirmations if you purchased online. If you registered your laptop with the manufacturer for warranty purposes, that registration may have stored the serial number in your account — log into the manufacturer's website and check your registered devices.

Understanding serial number formats by brand

Different manufacturers use different formats, so knowing what to look for helps you spot the right number. Dell uses a "Service Tag" that is usually 7 characters (letters and numbers), while HP and Compaq use serial numbers that are longer and often start with letters like "CN" or "SG." Lenovo serial numbers vary by model but are typically 8 to 12 characters. ASUS uses a mix of letters and numbers, often 10 to 12 characters long.

Apple's serial numbers are usually 12 characters and often include letters and numbers in a specific pattern. Acer and MSI also use alphanumeric codes of varying lengths. The key is that the serial number is always unique to your individual laptop — no two machines have the same one. If you see a number on the sticker that looks like a date or a simple sequence, it is probably the model number or batch code, not the serial number.

What to do if you cannot find the serial number

If the physical sticker is completely worn away and the operating system does not show a serial number, contact the laptop manufacturer's support team. You will need to provide proof of purchase or ownership — a receipt, warranty card, or photo of the laptop itself. The manufacturer can sometimes look up your serial number based on other information like the model number and your purchase date.

If you are trying to find the serial number for warranty or repair purposes, the manufacturer's support page usually has a tool to search by model number instead. You can also try using third-party system information tools like CPU-Z or GPU-Z, which sometimes display the serial number if the operating system does not. These are free programs that show detailed hardware information.

Frequently Asked Questions

Is the serial number the same as the model number?

No. The model number identifies the type of laptop (like "Dell XPS 13"), while the serial number is unique to your individual machine. The model number is usually shorter and appears on the sticker alongside the serial number. You need the serial number for warranty claims or repairs because it proves which specific laptop you own.

Can I find the serial number if my laptop won't turn on?

Yes. If your laptop does not power on, the physical sticker on the bottom or back is your only option. You do not need the laptop to be running to read a sticker. If the sticker is damaged, check your purchase receipt, warranty card, or original packaging for the number.

Why do I need my laptop's serial number?

Manufacturers and retailers use the serial number to verify ownership, process warranty claims, and track repairs. If your laptop is stolen, you can provide the serial number to police and the manufacturer to help recover it. Some software licenses and support registrations also require the serial number to confirm you own the device.

What if the serial number on the sticker does not match what Windows shows?

This is rare but can happen if the laptop was refurbished or if the sticker was replaced. The number in Windows System Information is usually more reliable because it comes directly from the hardware. If you are concerned about a mismatch, contact the manufacturer's support team with both numbers and your proof of purchase.

Can I change my laptop's serial number?

The serial number stored in your laptop's firmware cannot be changed by normal users — it is set by the manufacturer during production. The physical sticker can be removed or replaced, but doing so may void your warranty or cause problems if you need service. Never alter the serial number on a laptop you plan to return or sell.