You might think you'll never need to know your Windows product key, and the sticker attached to the bottom of your laptop or the scrap of paper on which you jotted it down may have long since worn away. Perhaps you never knew what it was in the first place.

But there are times, such as when reinstalling Windows or upgrading your machine, that you may be asked to enter it. And if you don't know what it is, it may already be too late to find it, and you really don't want to have to pay for Windows again.

Follow our advice below to make sure you have a record of your Windows product key.

Finding your Windows 10 Product Key using third-party software

Windows 10 is different to its predecessors, in that the key finding programs that worked so well in Windows XP, Vista, 7, and 8.1 aren’t much use now.

Using a paid program such as Recover Keys, or free versions like Magic Jelly Bean KeyFinder, may return a code, but there’s a very good chance that this will be a generic number used by the manufacturers, and not one that will work to activate your PC.

We've downloaded Magical Jelly Bean KeyFinder, which upon launch displays any Windows codes it has found.

Magical Jelly Bean Keyfinder

Finding your Windows Product Key if you upgraded for free or bought a digital copy from Microsoft

If you took advantage of the free upgrade to Windows 10 that Microsoft offered during its early days or bought a digital version of the OS from the Microsoft store, then you’ll have what’s called a Digital Licence (or Digital Entitlement) rather than a physical one.

This means that the Product Key is linked to your account, rather than kept on a sticker attached to the bottom of the PC. 

Should you find yourself stuck at the ‘It’s time to enter the Product Key’ stage of the installation process, simply click on the ‘Do this later’ option in the lower left corner of the screen and finish the process by logging into your Microsoft account. Just bear in mind you’ll need access to the internet for this to work.

how to find windows 10 product key

If you have a working Windows 10 PC of your own to hand then you can check whether you have a Digital Entitlement or not by going to Settings > Update & Security > Activation and seeing if it states that ‘Windows is activated with a digital licence linked to your Microsoft account’.

Windows 10 activation

This means that so long as you use your Microsoft account to login to your device during the installation process, you won’t need a code to activate Windows 10 as it will do so from your account instead.

If you haven't linked your Microsoft account, then follow these steps to do so:

  • Open the Settings app
  • Click on Accounts
  • Click on Your info
  • Click 'Sign in with a Microsoft account instead' link  (this won't be shown if your PC is connected to a work domain)
  • Sign in with your details
  • Enter your current Windows password
  • Either create a PIN or click 'Skip this step'

Finding your product key if you bought a new PC or a physical copy of Windows

The other way to find your Product Key is to look for the 25-character code that came with or on the packaging that accompanied your device. This will either be a card inside the box, a sticker on the DVD sleeve, or printed upon the Certificate of Authenticity (COA) attached to the PC.

how to find windows product keys DVD

However, this isn't always the case. One reader told us that, according to HP, it does not put product key on laptops or PCs for security reasons. As with the Digital Entitlement or Digital Licence, the product key is stored ‘somewhere in the computer’ and will activate automatically if needed. This is supposed to work even if the hard drive fails.

It’s worth noting that Microsoft states that it ‘doesn’t keep a record of purchased product software keys’ so if you’ve lost the packaging, and the sticker no longer displays the code, then we’re sorry to say that you might be out of luck.

Do I need a product key to reinstall Windows 10?

Since Microsoft has your computer’s ‘digital signature’ from the initial upgrade it recognises the combination of components when you do a clean install and automatically activates Windows. This means you can safely skip the screen which asks for a product key at the start of the installation process.

It’s just frustrating that there’s no message to tell you this: the screen is primarily for those installing a version of Windows 10 they’ve purchased and which therefore still requires a key.

So, even if you skip that screen on installation, Windows 10 should activate as long as you haven’t made any major changes to your PC. Upgrading from a hard disk to an SSD won’t affect anything, nor will changing your graphics card.

However, upgrading your motherboard and processor will probably count as ‘significant’ and you’ll have to ring Microsoft’s support line if you find that Windows is no longer activated, or you’re reinstalling it.