- VoIP & Phone Systems
Hosted vs On-Premise VoIP: Which Is Right for Your Business?
18 Mar, 2026
Free Tool
Email Storage Calculator
Estimate your mailbox storage requirements based on user count, email volume, retention policy, and attachment sizes — and see how it maps to Microsoft 365 limits.
Enter Your Details
e.g. info@, sales@, support@ mailboxes
Microsoft 365 Storage Limits by Plan
| Storage Feature | Basic (£4.60/user/mo) | Standard (£9.40/user/mo) | Premium (£16.60/user/mo) |
|---|---|---|---|
| Primary Mailbox | 50 GB | 50 GB | 50 GB |
| Archive Mailbox | 50 GB (auto-expanding) | 50 GB (auto-expanding) | 50 GB (auto-expanding) |
| Total per User (with archive) | 100 GB+ | 100 GB+ | 100 GB+ |
| Shared Mailbox | 50 GB (free) | 50 GB (free) | 50 GB (free) |
| OneDrive Storage | 1 TB per user | 1 TB per user | 1 TB per user |
| Max Message Size | 150 MB | 150 MB | 150 MB |
| Recoverable Items | 30 GB | 30 GB | 30 GB |
| Retention Policies | Basic | Basic | Advanced (Compliance) |
Storage limits are per Microsoft’s current allocation. Archive mailbox auto-expands beyond 50 GB for plans with Exchange Online Plan 2 or equivalent. View full Cloud Email details
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