How to Find a Serial Number on a Computer

Every computer has a serial number — a unique identifier assigned by the manufacturer at the factory. You might need it to register your device, file a warranty claim, get tech support, or track down a stolen machine. The tricky part is that where to find it depends entirely on your operating system, device type, and sometimes even the manufacturer.

Here's a practical breakdown of every reliable method.

Why Your Serial Number Matters

A serial number is different from a model number. The model number identifies a product line (e.g., "Dell XPS 15"). The serial number identifies your specific unit within that line. Manufacturers use it to track production batches, verify warranty status, and authenticate support requests.

If you're calling tech support without it, expect friction.

Method 1: Check the Physical Label 🔍

The fastest method — no software required.

• Laptops: Flip the device over. The serial number is usually on a sticker on the bottom panel, often near the battery compartment or regulatory information label.
• Desktops: Look on the side panel, rear panel, or top of the tower. On small-form-factor PCs, it's sometimes on the bottom.
• All-in-one PCs: Check the rear of the display housing.

The label typically includes the serial number, model number, and regulatory codes. The serial number is often labeled S/N or Serial No.

Caveat: Labels fade, peel, or get covered by asset tags in enterprise environments. If the physical label is unreadable, move to a software method.

Method 2: Find It in Windows (Built-In Tools)

Windows offers multiple ways to pull the serial number without opening a single settings panel.

Using Command Prompt or PowerShell

1. Press Windows + R, type cmd, and hit Enter.
2. Run this command:

wmic bios get serialnumber 

This queries the BIOS/UEFI firmware, which stores the serial number embedded by the manufacturer. On most machines, this returns the same number printed on the physical label.

You can run the same query in PowerShell:

Get-WmiObject Win32_BIOS | Select-Object SerialNumber 

Using System Information

1. Press Windows + R, type msinfo32, and hit Enter.
2. Look for System Information in the left pane.
3. Find System SKU or Serial Number in the right panel — though this field isn't always populated depending on the manufacturer.

Important distinction: Some manufacturers store the serial number in the BIOS firmware reliably; others leave the WMIC field blank or return a placeholder like To be filled by O.E.M. This is more common with custom-built desktops, where no single system serial number is assigned.

Method 3: Find It on a Mac 🍎

Apple makes this relatively straightforward.

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 panel (macOS Ventura and later may require clicking More Info, then scrolling to find it under system details).

Using Terminal

Open Terminal and run:

system_profiler SPHardwareDataType | grep "Serial Number" 

On the Hardware Itself

• MacBooks: Serial number is engraved on the bottom case, near the regulatory text.
• Mac mini: Bottom panel.
• iMac: Rear of the display stand.

Apple also links serial numbers to your Apple ID if the device has been signed in — accessible via appleid.apple.com under your registered devices.

Method 4: Check the BIOS/UEFI Directly

If an OS isn't booting or you're troubleshooting a fresh install, you can find the serial number in the firmware interface itself.

1. Restart the computer and press the firmware key during startup (F2, F10, DEL, or ESC — varies by manufacturer).
2. Navigate to a section called System Information, Main, or About.
3. The serial number and model number are typically listed there.

This is especially useful for enterprise IT environments where the OS may have been reimaged and software labels don't reflect original hardware identifiers.

Method 5: Check the Original Packaging or Documentation

If the machine is new or you kept the box, the serial number is almost always printed on a label on the outside of the retail box — typically on the bottom or side. It may also appear on the invoice or purchase receipt from the retailer or manufacturer's online store.

Variables That Affect Which Method Works

The WMIC command works reliably on most OEM Windows machines (Dell, HP, Lenovo, ASUS, etc.) because these manufacturers flash the serial number directly into firmware during manufacturing. Custom-built PCs don't have this — the motherboard may have its own serial, but there's no unified system serial number.

When the Serial Number Field Returns Nothing

If wmic bios get serialnumber returns a blank or placeholder value, it usually means:

• The machine was custom-built with no OEM serial assignment
• The BIOS was reset or reflashed improperly
• The motherboard was replaced without reprogramming the firmware

In these cases, check the motherboard's physical label (visible when the case is open), or use the motherboard model number instead to look up support documentation.

Your serial number is out there — the question is just which path gets you to it fastest given your specific machine, its condition, and whether you're working inside the OS or around it.