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Best Windows 10 product key finder of 2021

PRICE
VERDICT
REASONS TO BUY
REASONS TO AVOID
VERDICT
REASONS TO BUY
REASONS TO AVOID
Person typing on a laptop using the best product key finder
(Image credit: Pexels)

The best Windows 10 product key finders make it easy to find all your Microsoft serial numbers, for Windows or other software.

Product keys are one of the ways software developers protect their products against piracy. Unfortunately, they're easy to lose, which can be a real problem if you need to reinstall Windows or any other software from scratch

If you've bought a desktop PC or laptop with Windows 10 already installed, you'll probably find its product key on a Certificate of Authenticity sticker on the the case or in the included paperwork, but not if you've built your own PC and installed the operating system yourself.

Many other applications also require product keys if you reinstall them – including Microsoft Office – and if you've lost the email you received when you first installed them, you could be in real trouble later on.

Product key finders only work for software that's already installed, so download one and make a note of all your keys now, so you're prepared in advance.

If you want to optimize your computer, you can also check out our featured best free PC optimizer.

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(Image credit: Belarc)

1. Belarc Advisor

A wealth of information about your hardware and software

Reasons to buy
+Automatic updates+Lots of extra details
Reasons to avoid
-No security score for Windows 10

Belarc Advisor is primarily a tool for gathering information about your Windows system, including hardware, security updates and product keys.

Editor's choice award: Belarc Advisor

Whenever you run Belarc Advisor, it automatically checks its database for software definitions – essential for finding keys for new programs. After that, it scans your system and presents the findings in an HTML page in your default web browser. Scroll down to 'Software licenses' to find serial numbers and product keys for Windows, Office and many other applications.

Belarc Advisor offers a wealth of other information, including details of your antivirus software, connected hardware, and other devices on the same network. It also offers a security benchmark score, though sadly this is only available for Windows 7, Windows Vista and Windows XP Pro.

Belarc Advisor's scans are fast and offer so much more information than just serial numbers, it's our favorite free product key finder.

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(Image credit: Abelssoft)

2. Abelssoft MyKeyFinder

Displays your Microsoft product keys in a clear, searchable list

Reasons to buy
+Clean interface+Searchable results
Reasons to avoid
-Occasional ads in free version

There are two versions of Abelssoft MyKeyFinder: free and paid-for. Both will find Windows and Microsoft Office product keys but the Plus edition will also scan external hard drives and find Wi-Fi passwords. 

After MyKeyFinder has scanned scan your PC’s registry the results are presented in a clear list, ready to be copied to the clipboard with a single click. Unlike many product key finders, MyKeyFinder won’t throw up duplicate keys and the results can be searched and filtered.

You can also add programs and keys not detected by MyKeyFinder as standard, then export the full list as a PDF so they’re all in one convenient location.

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(Image credit: Klinzmann)

3. LicenseCrawler

Find the keys for Windows and a wealth of other software

Reasons to buy
+Identifies dozens of applications+Portable
Reasons to avoid
-Slow scans-Occasional ads

LicenseCrawler will find the license key for pretty much any application that has one, and it's free for home use. Its scan of the Windows registry takes a long time to complete – even if you select the 'high speed' option – but you can limit its scope using the blacklist and whitelist filters.

LicenseCrawler is distributed as a portable app, meaning you don't have to install it on the Windows system you're scanning – just download the zip file, extract its contents and run LicenseCrawler.exe. This is particularly handy if you have several PCs; just download it to a USB stick and you can just plug it in and run it on any of them.

The only downside of LicenseCrawler is the occasional pop-up ad, but finding product keys isn't a task you'll be performing every day, so they're only a minor inconvenience.

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(Image credit: RJL Software)

4. Windows Product Key Viewer

A quick way to find your Windows product key, but nothing else

Reasons to buy
+Super fast scans+Portable app
Reasons to avoid
-Only finds Windows keys-Some misleading ads on site

Windows Product Key Viewer is super fast, taking barely a second to scan your system and present the results. That's because, as the name suggests, it only supplies the product key for your operating system.

That shouldn't necessarily put you off though. Although it doesn't find serial numbers for other applications, it does provide some extra information about your OS, including the registered user, install date and last boot time, and it's compatible with versions of the operating system from Windows 10 all the way back to Windows 95. 

Take care when downloading the software – the site includes some ads that look like download buttons for the software, but are in fact unrelated. Only click the link 'Download Windows Product Key Viewer'.

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(Image credit: MIS Utilities)

5. Free PC Audit

A super simple way to find your Windows 10 product key

Reasons to buy
+Very simple to use+Portable
Reasons to avoid
-Only finds Windows keys

Free PC Audit is another portable application, and doesn't even come as a zip archive – just download the exe file and run it to begin scanning.

Like Belarc Advisor, Free PC Advisor provides a wealth of information about your whole system – not just its software – though its interface isn't quite as intuitive. It's compatible with all versions of Windows, from NT all the way through to Windows 10, but doesn't find keys for Microsoft Office or any other software.

It also provides lists of all installed software and running system processes, though this information is readily available through Windows itself. 

Additionally, if you're interested in making your business computers run more smoothly and efficiently check out our featured best system utilities and repair software.

Desire Athow

Managing Editor, TechRadar Pro

Désiré has been musing and writing about technology during a career spanning four decades. He dabbled in website building and web hosting when DHTML and frames were en vogue and started writing about the impact of technology on society just before the start of the Y2K hysteria at the turn of the last millennium. Then followed a weekly tech column in a local business magazine in Mauritius, a late night tech radio programme called Clicplus and a freelancing gig at the now-defunct, Theinquirer, with the legendary Mike Magee as mentor. Following an eight-year stint at ITProPortal.com where he discovered the joys of global techfests, Désiré now heads up TechRadar Pro. He has an affinity for anything hardware and staunchly refuses to stop writing reviews of obscure products or cover niche B2B software-as-a-service providers.