The best Windows 10 product key finders make it simple and easy to find your Microsoft serial numbers, for Windows and 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 (opens in new tab) 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 (opens in new tab) – 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.
The best Windows 10 product key finder of 2022 in full:
Why you can trust TechRadar Our expert reviewers spend hours testing and comparing products and services so you can choose the best for you. Find out more about how we test.
Belarc Advisor is primarily a tool for gathering information about your Windows system, including hardware, security updates and product keys.(opens in new tab)
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.
There are two versions of 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.
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.
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'.
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.
Which Windows 10 product key finder is best for you?
When deciding which Windows 10 product key finder to download and use, first consider what your actual needs are, as sometimes free platforms may only provide basic options, so if you need to use advanced tools you may find a paid platform is much more worthwhile. Additionally, free and budget software options can sometimes prove limited when it comes to the variety of tools available, while higher-end software can really cater for every need, so do ensure you have a good idea of which features you think you may require.
How we tested the best Windows 10 product key finder
To test for the best Windows 10 product key finder we first set up an account with the relevant software platform, whether as a download or as an online service. We then tested the service to see how the software could be used for retrieving keys for both Windows and other software. The aim was to push each product to see how useful it was in a range of different situations.
If you're interested in making your business computers run more smoothly and efficiently check out our featured best system utilities and repair software.