How do I redeem a 3 year subscription

To confirm the 3 years were applied correctly and avoid being charged before then:

1. Go to the Microsoft account, Services & subscriptions page and sign in with the same Microsoft account used when redeeming the keys.
2. Check the Microsoft 365 subscription status there.
   • If the keys were redeemed correctly, the subscription should appear and show the updated expiration date.
   • Microsoft 365 lets multiple product keys extend the time on the same subscription, up to a maximum of 5 years.
3. If recurring billing is turned on and charging before the stacked term ends is a concern, go to the Payment & billing page for the subscription and review whether it shows:
   • Has recurring billing
   • or Expires on [date]
4. If it shows Has recurring billing, select Change and turn off recurring billing if that is preferred.

Important details:

• Entering more than one product key extends the subscription duration; it does not add more installations or storage.
• Always verify the keys were redeemed to the correct Microsoft account.
• If a product key was already redeemed, it is no longer needed for installation. Use the Microsoft account to manage and install Microsoft 365.

References:

• How to renew your Microsoft 365 subscription | Microsoft Support
• Problems renewing a Microsoft 365 subscription | Microsoft Support
• Using product keys with Microsoft 365 | Microsoft Support
• 3 years subscription? - Microsoft Q&A