Outlook storage size

Microsoft personal accounts cannot be merged or combined, and storage from one account cannot be transferred to another. Each Microsoft account keeps its own Outlook mailbox and its own Microsoft cloud storage quota.

Key points from the scenario and options:

1. Why the Outlook mailbox is limited while the Microsoft 365 account has 1 TB
   • Free accounts get 5 GB of Microsoft cloud storage and 15 GB of Outlook.com email storage on that specific account.
   • A Microsoft 365 subscription (Basic/Personal/Family) increases storage only for the account that owns the subscription; it does not extend to a different Outlook/Microsoft account.
   • Because the Outlook account in use is separate from the subscription account, it is still using the free quotas.
2. Combining or transferring accounts
   • It is not possible to link, merge, or combine Microsoft personal accounts, and things like mailbox, purchases, or storage cannot be moved between them.
   • Accounts can only be used side by side.
3. Options to keep using the existing Outlook address Since the Outlook address is the one to keep, and the subscription is on a different account:
   • The subscription cannot be “moved” to the Outlook account by merging accounts.
   • To benefit from increased storage on the Outlook address, the subscription would need to be associated with that Outlook account instead (which may require canceling the current subscription on the other account and then purchasing a new subscription while signed in with the Outlook account).
   • Canceling a subscription does not delete the Microsoft account or its email address; the account remains, just without the subscription benefits.
4. Using multiple accounts side by side
   • Both accounts can be added to Outlook so that both mailboxes are accessible in one place, but their storage and subscriptions remain separate.

Practical path based on the constraints described:

• If the current subscription account’s email is not important, cancel that subscription on that account.
• Sign in with the Outlook account and purchase the desired Microsoft 365 subscription there so that the Outlook mailbox and cloud storage on that account receive the upgraded quotas.
• The old subscription account will remain as a separate Microsoft account but without the paid subscription.

References:

• Combining Microsoft accounts
• Microsoft storage FAQs
• Microsoft storage quotas
• Frequently asked questions about Microsoft 365 Basic
• Storage limits in Outlook.com
• Changes to Microsoft 365 email features and storage