Your product key is printed on a sticker or buried in your system settings, depending on how you got Windows

Your Windows 10 product key is a 25-character code that proves you own a copy of Windows. Where you find it depends on whether you bought Windows separately, it came pre-installed on your computer, or you upgraded from an older version. Most people never need to look for it — but if you're reinstalling Windows, troubleshooting set up, or moving to a new device, you'll need to know where it is.

The fastest way to find it is usually in your system settings. If that doesn't work, check the physical sticker on your device or your email receipt. Microsoft also keeps a record tied to your account if you bought it through the Microsoft Store.

Key Takeaways

  • Check Settings > System > About > Windows set up to see if your product key is stored in your system and whether Windows is currently activated.
  • If you bought Windows 10 on a disc or USB drive, the product key is on the packaging or inside the case.
  • Computers that came with Windows pre-installed have the product key on a sticker on the device itself, usually on the bottom or back.
  • If you upgraded from Windows 7 or 8, your old product key may not work — check your Microsoft account or contact the device manufacturer.
  • Third-party tools can read your product key from your system, but only if Windows is already activated on that device.

Check your system settings first

Open Settings by pressing the Windows key and typing "Settings", then select the Settings app. Go to System, then scroll down and select About. Look for the section labeled "Windows set up" — it will show whether Windows is activated and may display your product key.

If your product key appears here, you're done. If it doesn't, Windows may have been activated using a digital license tied to your Microsoft account instead of a traditional product key. This is common on newer devices and means you don't need a separate key — your account is your proof of ownership.

Look for a physical sticker on your device

If you bought a computer with Windows already installed, the product key is usually on a sticker attached to the device. Check the bottom, back, or side of your laptop or desktop tower. The sticker shows a 25-character code in groups of five letters and numbers separated by hyphens.

On some older laptops, the sticker may be under the battery or on the inside of the case. If your device is very new, the manufacturer may have stopped using physical stickers and instead tied the key to your account — in that case, the Settings method above is your only option.

Check your email and purchase receipts

If you bought Windows 10 as a standalone product — either as a physical disc or a digital read — the product key was included in your receipt or confirmation email. Search your email for messages from Microsoft, the retailer you bought from, or your email confirmation from the purchase.

For digital purchases through the Microsoft Store, sign into your Microsoft account at account.microsoft.com, go to Your Orders, and look for Windows 10. The product key should be listed there or available to view in your order details.

Use a third-party tool if Windows is already activated

If you can't find your key through the methods above and Windows is currently activated on your device, you can use a free tool to read the key from your system. Programs like ProduKey (from Nirsoft) or Belarc Advisor can scan your computer and display the product key that's stored there.

These tools only work if Windows is already activated. They read information that's already on your device — they don't retrieve it from Microsoft or bypass set up. read only from the official website of the tool you choose, not from third-party read sites.

What to do if you upgraded from Windows 7 or 8

If you upgraded to Windows 10 from an older version of Windows, your old product key usually won't work anymore. Microsoft issued a new key when you upgraded, and that new key is what you need if you ever reinstall Windows 10.

Check your Settings > System > About section for your current Windows 10 key. If you can't find it there, contact the manufacturer of your device — they may have a record of the key they issued when you upgraded. If you bought the upgrade directly from Microsoft, check your email for the confirmation and new key.

Understand the difference between a product key and a digital license

Newer devices often use a digital license instead of a traditional product key. A digital license is tied to your device's hardware and your Microsoft account, not a 25-character code. If Windows shows "activated" in your Settings but you can't find a product key anywhere, you have a digital license.

A digital license is actually more convenient — if you reinstall Windows on the same device, it reactivates automatically when you sign in with your Microsoft account. You don't need to enter a key. If you move to a different device, you'll need to purchase a new license or contact Microsoft support to transfer it.

Frequently Asked Questions

Can I use someone else's product key on my computer?

No. Each product key is licensed to one device at a time. If you use someone else's key, their copy of Windows will be deactivated. If you need Windows on a second device, you need to purchase a separate license.

What if my product key doesn't work when I try to reinstall Windows?

The key may have already been used on another device, or it may be tied to a different version of Windows. Check that you're installing the same edition (Home, Pro, etc.) that the key was issued for. If the key is genuinely invalid, contact Microsoft support or the retailer you bought it from.

Do I need my product key to use Windows 10?

Not necessarily. If your device has a digital license, Windows will stay activated without a key. If you're reinstalling Windows on the same device, the digital license reactivates automatically. You only need the key if you're moving Windows to a different device or if Windows asks you to set up it.

Is it safe to share my product key online if I need help?

No. Treat your product key like a password. If someone has your key, they can use it to set up Windows on their device, which will deactivate it on yours. Never post it in forums or send it to someone you don't trust, even if they claim to be from Microsoft support.

What happens if I lose my product key?

If Windows is currently activated on your device, you can use a third-party tool to read the key from your system. If you've already lost access to the device, contact Microsoft support with proof of purchase — they may be able to help you recover or reissue the key.