How to Check Your Computer's Serial Number (Windows, Mac & More)

Every computer ships with a unique serial number — a manufacturer-assigned identifier that's essential for warranty claims, tech support, insurance records, and device tracking. Knowing where to find it (and which method works for your setup) can save you a lot of frustration.

What Is a Computer Serial Number?

A serial number is a unique alphanumeric string assigned to your specific unit during manufacturing. It's different from a model number, which identifies the product line — your serial number identifies your individual machine.

Manufacturers use it to:

• Verify warranty status and coverage dates
• Process repairs, returns, and replacements
• Track stolen or lost devices
• Identify exact hardware configurations for a given unit

Serial numbers typically range from 8 to 20 characters and combine letters and numbers. The format varies by manufacturer — Dell, HP, Lenovo, Apple, and others each use their own conventions.

How to Find a Serial Number on Windows

Method 1: Command Prompt (Works on Most Windows PCs)

This is the fastest method and works without opening the case or finding the original box.

1. Press Windows + R, type cmd, and hit Enter
2. In the Command Prompt window, type:

wmic bios get serialnumber 

3. Press Enter — your serial number appears on the next line

This pulls the serial number stored in the system's BIOS/UEFI firmware, which is the most reliable software-based source.

Method 2: PowerShell

1. Right-click the Start menu and select Windows PowerShell
2. Type:

Get-WmiObject Win32_BIOS | Select-Object SerialNumber 

3. Press Enter

Both Command Prompt and PowerShell pull from the same BIOS data source, so the result should be identical.

Method 3: System Information Tool

1. Press Windows + R, type msinfo32, press Enter
2. In the System Information window, look for System SKU or scroll through the System Summary

Note: Not every manufacturer writes the serial number into this view — the command prompt method is more consistently reliable.

⚠️ A Common Windows Caveat

On some custom-built PCs or older machines, the serial number stored in BIOS may appear as a placeholder string like Default String or To Be Filled By O.E.M. This means the motherboard manufacturer didn't program a unique identifier — you'll need to check the physical label on the chassis instead.

How to Find a Serial Number on macOS

Method 1: About This Mac

1. Click the Apple menu (top-left corner)
2. Select About This Mac
3. The serial number appears directly in that window (on macOS Ventura and later, click More Info then scroll to find it under system details)

Method 2: System Information App

1. Hold Option and click the Apple menu
2. Select System Information
3. Under the Hardware Overview section, you'll see the Serial Number (system) field

Method 3: Terminal

For those who prefer the command line:

system_profiler SPHardwareDataType | grep Serial 

This outputs the serial number alongside other hardware identifiers.

Physical Label: The Universal Fallback 🔍

Regardless of operating system, every manufacturer prints the serial number on the physical device. Common locations include:

If the label has worn off — common on heavily used laptops — the software methods above become especially important.

Checking Serial Number via BIOS/UEFI

If your operating system won't boot, you can often find the serial number in the BIOS/UEFI setup screen:

1. Restart your computer
2. Press the BIOS entry key during startup (commonly F2, F10, Del, or Esc — varies by manufacturer)
3. Look for a System Information or Main tab

This method is particularly useful for troubleshooting scenarios where the OS is unresponsive.

Variables That Affect Which Method Works for You

Not every method works equally across all setups. Several factors determine your best path:

Operating system version — The steps for macOS Ventura differ from macOS Monterey. Windows 11 and Windows 10 behave similarly, but older versions may have different menu paths.

Manufacturer practices — Some manufacturers (particularly budget or white-label PC makers) don't consistently program serial numbers into BIOS firmware. Enterprise-grade machines from brands like Dell, HP, and Lenovo tend to have more reliable software-accessible serial numbers than consumer-grade or custom builds.

Physical condition — Worn labels, replaced chassis parts, or refurbished units may have missing, altered, or mismatched serial numbers between the physical label and the firmware.

Custom-built desktops — If you assembled the PC yourself, there's no system-level serial number in the traditional sense. The motherboard will have its own serial number (accessible via wmic baseboard get serialnumber), but it's not the same as a manufacturer-assigned device serial.

Virtualized environments — If you're running Windows inside a virtual machine, the serial number returned via WMIC will reflect the VM configuration, not the physical host hardware.

🖥️ Enterprise and IT Scenarios

For IT administrators managing fleets of machines, serial numbers are typically collected through device management platforms like Microsoft Endpoint Manager (Intune), JAMF (for Macs), or vendor-specific tools like Dell Command Monitor or HP Client Management. These platforms can pull serial numbers remotely across hundreds of devices simultaneously — a different use case from an individual checking their own machine.

If you're in a managed environment, your IT department may already have this information catalogued and accessible through an internal asset management system.

When the Serial Number Doesn't Match

Occasionally, the serial number stored in firmware doesn't match the one printed on the physical label. This can happen after:

• Motherboard replacement (the new board has its own programmed number)
• Refurbishment processes that don't reprogram firmware
• Certain repair workflows that swap components

For warranty and support purposes, manufacturers typically prioritize the physical label as the authoritative identifier — but it's worth confirming with the specific manufacturer's support process, since policies vary.

The right method ultimately depends on what your machine is, what state it's in, and what you need the serial number for — factors only visible from where you're sitting.