Serial numbers are printed or engraved on your device, usually on the back, bottom, or inside the battery compartment

A serial number is a unique identifier assigned to your specific device at the factory. It looks like a string of letters and numbers — typically 8 to 20 characters long — and no two devices share the same one. You need it when you contact support, register a warranty, or sell the device, because it proves which exact machine you own.

The location depends on what you're looking for. Laptops usually have it on the bottom or back panel. Phones and tablets print it on the back casing or inside the SIM tray. Desktops often put it on the side or rear panel. Monitors and external drives label it on the back. If you can't find a physical label, your operating system can show it to you in seconds.

Key Takeaways

  • Physical serial numbers are usually on the back, bottom, or inside removable parts like battery compartments or SIM trays.
  • Windows shows your serial number in System Information; macOS shows it in About This Mac; phones show it in Settings under About.
  • Take a photo of the physical label so you have it saved if the label wears away or you need to reference it later.
  • The serial number is different from the model number — the model tells you what device you have, the serial tells you which one.

Finding the serial number on laptops

On Windows laptops, flip the device over and look at the bottom panel. Most manufacturers print a label with the model, serial number, and other specs. The serial number is usually listed as "SN", "Serial Number", or "S/N". If the label is worn or missing, you can find it in Windows by opening the Start menu, typing "System Information", and clicking the result. Look for "System Serial Number" in the window that opens.

On MacBooks, the serial number is printed on the bottom of the chassis. You can also find it by clicking the Apple menu in the top left, selecting "About This Mac", and looking for "Serial Number" in the window. Apple calls it the "Serial Number (SN)" and it's always visible on this screen.

Finding the serial number on phones and tablets

On iPhones and iPads, go to Settings, tap General, then tap About. Scroll down and you'll see "Serial Number" listed. You can also find it by removing the SIM tray — the serial number is sometimes printed inside the tray slot as well.

On Android phones, go to Settings, scroll to About Phone (or About Device), and look for "Serial Number" or "Device Serial Number". Some Android devices also print it on the back casing under the model number. If you can't find it in Settings, try removing the SIM tray, which often has the serial number printed inside.

Finding the serial number on desktops and towers

Desktop computers usually have the serial number on a label on the back or side of the case. Look for a sticker with the manufacturer's logo and a string of characters labeled "SN" or "Serial Number". If the case is sealed or the label is missing, you can find it through your operating system the same way you would on a laptop — open System Information on Windows or About This Mac on a Mac.

If you built your own desktop from separate components, each part (motherboard, graphics card, power supply) has its own serial number, but the system as a whole does not. In that case, you may need the motherboard serial number instead, which is usually printed on the board itself or visible in the BIOS settings.

Finding the serial number on monitors and external drives

Monitors have serial numbers printed on a label on the back panel, usually near the power input or mounting bracket. Look for a sticker with the manufacturer name and a string of characters. External hard drives and USB drives also have labels on the back or bottom with the serial number listed.

For external drives connected to your computer, you can also find the serial number through your operating system. On Windows, right-click the drive in File Explorer, select Properties, then look for the serial number in the Details tab. On Mac, select the drive on the desktop, press Command+I, and look for "Serial Number" in the info window.

What to do if the label is worn or missing

If the physical label is faded or gone, your operating system is your backup. Windows, macOS, iOS, and Android all store the serial number in their system information, and you can retrieve it without opening the device. This is also the safest method if you're uncomfortable removing panels or taking apart your device.

Take a photo of the label while it's still readable, even if you don't need it right now. Store the photo in your phone or cloud storage so you have it if the label wears away further. If you ever need to prove ownership or file a warranty claim, having a photo of the original label is stronger evidence than typing the number from memory.

Serial number versus model number

The model number tells you what kind of device you have — for example, "MacBook Pro 16-inch" or "iPhone 15". The serial number tells you which specific device you own. Think of it like the difference between "Toyota Camry" (model) and your car's VIN (serial). Support teams use the serial number to look up your exact device's history, warranty status, and repair records.

On most labels, both numbers appear together. The model number is usually shorter and more recognizable. The serial number is longer and looks more random. If you're unsure which is which, take a photo of the whole label and send it to support — they can identify both numbers from the image.

Frequently Asked Questions

Can I find my device's serial number if I don't have the physical device?

If you have the original box or paperwork, the serial number is usually printed on the receipt, invoice, or warranty card. If you bought it online, check your email for the order confirmation or shipping label — many retailers include the serial number there. If you registered the device with the manufacturer, you can also log into your account on their website to find it.

Is the serial number the same as the IMEI or ICCID?

No. The IMEI is a phone-specific number that identifies your device on cellular networks. The ICCID is your SIM card's number. The serial number is separate and identifies your physical device. On phones, you can find all three in Settings under About, but they are different identifiers used for different purposes.

What if two devices have the same serial number?

This should not happen — serial numbers are unique to each device. If you see the same number on two devices, one of them is counterfeit or the label has been copied. Contact the manufacturer with photos of both devices and the serial numbers. Legitimate devices always have unique serial numbers.

Do I need the serial number to use my device?

No. The serial number is only needed for support, warranty claims, registration, or resale. Your device works normally without ever looking it up. You only need it when you contact the manufacturer or a repair shop, or when you want to register the device for warranty coverage.

Can I change my device's serial number?

No. The serial number is burned into the device's firmware or hardware at the factory and cannot be changed without specialized equipment. Attempting to change it is illegal in most places and voids your warranty. If you need a replacement device, contact the manufacturer or retailer.