What is a product key?

Watch a video about where to find your product key. (To view captions in your language, tap or click the Closed captioning button Closed Captioning button.)

A product key is a 25-character code that's used to activate Windows. Activation helps to verify that Windows hasn't been used on more PCs than the Microsoft Software Licence Terms allow.

Your product key is on a card inside the box that the Windows DVD came in, or in an email that shows that you've bought Windows. It looks like this: PRODUCT KEY: XXXXX-XXXXX-XXXXX-XXXXX-XXXXX. If you bought a PC with Windows pre-installed, contact the PC manufacturer for the original key.

It's a good idea to save a copy of your product key for your records in case you ever need to reinstall Windows.

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