Windows · PC · about 5 minutes · updated July 1, 2026
How to activate Windows 11 with a product key
Whether you have just built a PC, reinstalled Windows or want the "Activate Windows" watermark gone, this is how to enter your key and confirm Windows 11 is activated.
Before you start
- A Windows 11 key matching the edition installed (Home or Pro)
- An administrator account on the PC
- An internet connection
-
01
Check which edition you have
Settings → System → About and read the Edition line. Your key must match it — a Pro key will not activate Home without an upgrade (covered in a separate guide).
-
02
Open the Activation page
Settings → System → Activation. You will see the current state and a Change product key option.
-
03
Enter the key
Click Change, type the 25 characters and press Next. Windows contacts the activation servers; this takes a few seconds.
-
04
Confirm
The page should now read Windows is activated with a digital licence. The desktop watermark disappears after a restart.
-
05
Link it to your Microsoft account
Sign in to Windows with a Microsoft account. The licence is then stored as a digital licence, which makes reactivation after a hardware change far easier.
If something goes wrong
Common snags.
Error 0xC004C003 or "this key is blocked"
Usually a typo or an edition mismatch. Re-type carefully — 8 and B, 0 and D look alike. Still stuck? Send us a screenshot.
Error 0xC004F050
The key is valid but the edition on the PC is different. See the Home → Pro upgrade guide.
No internet on that PC
Press Start, type <em>slui 4</em> and press Enter to use the automated telephone activation service.
Keep reading