To change the phone number used for SMS or call-based two-factor authentication (MFA) with your Microsoft account, you must update your security information on the Microsoft account website, not inside the Microsoft Authenticator app itself. This is the key distinction to understand when you need to change phone number Microsoft authenticator, as the app only stores generated codes and does not manage the phone number used for receiving verification texts or calls.
Where to change phone number on Microsoft Authenticator (it's not in the app)
The Microsoft Authenticator app does not directly store or allow you to change the phone number used for SMS or call-based MFA. This confusion arises because users expect to update their contact details within the app they use for authentication. Instead, the phone number for receiving codes via text or call is managed as part of your Microsoft account's security information. You must go to the Microsoft account security page or the "My Sign-ins" portal to make this change. The Authenticator app itself only manages the time-based codes and push notifications for accounts already added to it.
How to update your phone number for a personal Microsoft account
- Navigate to the Microsoft account security page at account.microsoft.com/security or directly to account.live.com/proofs/manage/additional.
- Sign in with your personal Microsoft account credentials. You may be prompted to verify your identity using an existing method.
- On the "Security info" or "Recovery options" page, locate the existing phone number entry.
- Select "Delete" to remove the old phone number from your account.
- Choose "Add sign-in method" or "Add a new phone number."
- Select "Phone" as the method, then enter your new phone number.
- Complete the verification process by receiving a code via SMS or a phone call and entering it when prompted.
This process directly addresses the need for updating phone number on apps and accounts, ensuring your MFA method is current without any changes made inside the Authenticator app itself.
How to update your phone number for a work or school account
- Go to mysignins.microsoft.com/security-info or aka.ms/mfasetup.
- Sign in using your work or school account. If prompted, use an alternative MFA method you still have access to, such as another authentication app or a hardware token.
- On the "Security info" page, find the old phone number entry and select "Delete" to remove it.
- Select "Add method," choose "Phone," and enter your new phone number.
- Complete the verification process by following the prompts to receive and confirm a code via SMS or call.
For organizational accounts, this is the correct procedure to change Microsoft phone number, as the Authenticator app cannot modify this information directly.
What to do if you can't access your old phone number
If you cannot access your old phone number or any other MFA method you previously registered, the recovery path depends on your account type. For work or school accounts, you must contact your organization's IT Service Desk or Help Desk. They can reset your MFA registration in the Microsoft Entra admin center, which will prompt you to register new security methods the next time you sign in. For personal Microsoft accounts, you will need to use the account recovery options provided on the Microsoft login page, which may involve verifying your identity through an alternate email address or answering security questions. If you are locked out entirely, Microsoft's account recovery process is the only option to regain access.
How to transfer Microsoft Authenticator to a new phone
Transferring the Authenticator app's stored accounts to a new phone is a separate process from changing your phone number. To do this, first enable "Cloud Backup" on iOS or "Cloud Backup/Cloud Sync" on Android within the Authenticator app's settings on your old device. On your new phone, install the Microsoft Authenticator app and choose "Begin recovery" or "Restore from backup." Sign in with the same personal Microsoft account you used for the backup to restore your accounts. For work or school accounts restored via backup, you will need to complete additional sign-in and setup steps on the new phone to reactivate them. It is crucial to verify that all accounts are working correctly on the new device before erasing or disposing of the old phone.
Common issues when changing your Microsoft Authenticator phone number
Several issues can arise during this process. If a phone number is already associated with another Microsoft account, you might be prompted to "Transfer number" or "Sign in." If the "Transfer number" option is unavailable, a 30-day waiting period may apply before you can use that number. For work or school accounts, ensure the new phone number is unique within your organization's tenant to avoid errors. Additionally, some Microsoft documentation indicates that phone numbers may no longer be added as a new sign-in verification method, with recommendations to use the Authenticator app, recovery email, or passkey instead. This shift reflects a broader move toward app-based authentication over SMS for improved security. When removing phone numbers from accounts, always verify that you have at least one other working MFA method to avoid being locked out.
Frequently Asked Questions
Will changing my phone number on the Microsoft account website affect the codes in the Authenticator app?
No, changing your phone number on the security page only updates the method for receiving SMS or call-based codes. The time-based codes already stored in the Authenticator app for your accounts will continue to work without interruption.
Can I have multiple phone numbers on my Microsoft account for MFA?
Yes, you can add more than one phone number as a sign-in method. This provides a backup option if you lose access to your primary number. Simply repeat the "Add sign-in method" process for each additional number.
What happens to my work or school accounts in the Authenticator app if I change my phone number?
The accounts in the app remain functional unless your organization requires re-registration. However, updating your phone number on the security info page ensures you can still receive SMS codes if needed, and it does not remove the app-based authentication methods already configured.
Why does the Authenticator app not show an option to change my phone number?
The app is designed to store and generate authentication codes, not to manage the phone number used for SMS or call verification. That number is part of your broader Microsoft account security profile, which is only editable through the web-based security pages.
How long does it take for the new phone number to become active after I update it?
Once you complete the verification process for the new number, it becomes active immediately. You can use it for sign-in or recovery right away, though some organizational accounts may have a short propagation delay.
