How to Find the Serial Number on a Laptop: Every Method Explained

Your laptop's serial number is its unique fingerprint — no two devices share the same one. You'll need it to register a warranty, request technical support, report a theft, or check if your device qualifies for a recall or repair program. The good news is there are several reliable ways to find it, and at least one will work regardless of your situation.

Why the Serial Number Matters

A serial number (sometimes called an S/N) is assigned by the manufacturer during production. It identifies your specific unit, not just the model. When you contact support, they use it to pull up your exact hardware configuration, warranty status, and service history. It's different from the model number, which identifies a product line — thousands of people share a model number, but your serial number belongs only to your device.

Method 1: Check the Physical Label on the Laptop 🔍

The most direct method is to look at the laptop itself. Manufacturers typically print the serial number on a sticker or engraving in one of these locations:

• Bottom of the laptop — the most common spot, usually on a white or silver label
• Inside the battery compartment — remove the battery if it's removable
• Under a removable panel — less common, but found on some business-class machines
• On the original box — the retail packaging almost always has a barcode label with the serial number printed beneath it

The label will usually show multiple identifiers. Look specifically for text labeled "S/N", "Serial No.", or "Serial Number". The serial number itself is typically a mix of letters and numbers, anywhere from 8 to 20 characters depending on the manufacturer.

Method 2: Find It Through Windows Settings or Command Line

If the sticker is worn, missing, or hard to read, Windows can retrieve the serial number stored in the system firmware.

Using System Information:

1. Press Windows + R, type msinfo32, and hit Enter
2. In the System Summary panel, look for "System SKU" or scroll to find the serial number — note that not all manufacturers embed it here

Using Command Prompt (most reliable on Windows):

1. Open Command Prompt (search "cmd" in the Start menu)
2. Type the following and press Enter:

   wmic bios get serialnumber 

3. The serial number will display on the next line

Using PowerShell:

Get-WmiObject -Class Win32_BIOS | Select-Object SerialNumber 

Both commands pull the serial number directly from the BIOS/UEFI firmware, so they work even if the physical label is damaged. If the result returns "To Be Filled by O.E.M." or a string of zeros, the manufacturer didn't program the serial number into the firmware — a known issue on some older or budget machines.

Method 3: Find It on a Mac 🍎

Apple makes this straightforward across all methods:

From the Apple menu:

1. Click the Apple logo in the top-left corner
2. Select "About This Mac"
3. The serial number appears directly in the overview window

From System Settings (macOS Ventura and later):

1. Go to Apple menu → System Settings → General → About
2. The serial number is listed and can be clicked to copy it

Using Terminal:

system_profiler SPHardwareDataType | grep "Serial Number" 

Apple also links serial numbers to your Apple ID if the device has been signed in, so you can find it through appleid.apple.com under your registered devices.

Method 4: Check the BIOS/UEFI Directly

If you can't boot into your operating system — say, the laptop won't start properly — you can still access the serial number through the BIOS/UEFI setup menu:

1. Power on or restart the laptop
2. Press the BIOS access key immediately during startup (common keys: F2, F10, F12, DEL, or ESC — varies by manufacturer)
3. Navigate to a tab labeled "Main", "System Information", or "About"
4. The serial number is usually listed alongside the model number and BIOS version

This method is especially useful for technicians or when the OS is corrupted.

How Serial Number Format Varies by Manufacturer

Dell specifically uses the term "Service Tag" rather than serial number — it functions identically for support purposes but is only 7 characters.

When the Serial Number Isn't Where You Expect It

A few situations complicate the search:

• Replaced bottom case or cover: If a repair shop replaced the chassis, the original sticker may be gone. The firmware-stored serial number is your best fallback.
• Refurbished or resold laptops: Some units have had stickers removed or replaced. Check both the physical label and software methods to confirm they match.
• Linux systems: Use the terminal command sudo dmidecode -s system-serial-number to retrieve the firmware-stored value.

What Determines Whether You Can Find It Easily

The ease of locating a serial number depends on a few variables: the age of the device (older machines are less consistent about storing it in firmware), the manufacturer's practices (premium brands tend to be more thorough), whether the physical label is intact, and the operating system you're running. On a modern, well-maintained laptop from a major brand, you'll likely have multiple working methods available simultaneously — on an older or heavily modified machine, you may need to try more than one approach before you land on a reliable result.