License & Subscription Issues

Microsoft 365 E3 Storage Limits Explained: Mailbox, OneDrive, and SharePoint

Khadija Khan Oct 12, 2026 873 views

Question details

The user needs clarification on the exact storage limits and eligibility requirements for Exchange Online, OneDrive, and SharePoint under a Microsoft 365 E3 subscription.

Understanding Microsoft 365 E3 Mailbox, OneDrive, and SharePoint Storage Limits

Product: Microsoft 365 E3
Device & OS: not provided
Scenario: Planning or managing enterprise cloud storage and checking eligibility for expanded OneDrive capacity.
Observed behavior: Seeking information on the default 100 GB mailbox limit, the five-license requirement for up to 25 TB of OneDrive storage, and overall SharePoint tenant allocation.

Before you start

Ensure you have global admin or SharePoint admin privileges in your Microsoft 365 Admin Center to check user eligibility and modify default storage limits.

Solution 1Recommended

Check Eligibility and Configure OneDrive Storage Limits

Verify if your Microsoft 365 tenant qualifies for increased OneDrive storage and configure the default limits for eligible users.

By default, OneDrive provides 1 TB of storage per user. However, Microsoft 365 E3 subscriptions can qualify for up to 5 TB or even 25 TB of storage if specific licensing conditions are met.

Verify the Minimum License Requirement

Ensure that your organization has assigned at least five Microsoft 365 E3 (or equivalent) licenses. This 5-user minimum is strictly required to qualify for increased OneDrive storage beyond the default 1 TB.

Run the Diagnostics Tool

Go to the Microsoft 365 Admin Center, open the 'Help & Support' widget, and type 'Check OneDrive site eligibility for increased storage' to run the diagnostic tool on specific user accounts.

Set Default Storage Space

Navigate to the SharePoint admin center, click on 'Settings', select the 'OneDrive storage limit' option, and enter the new default storage amount (e.g., 5120 GB) for your eligible users.

Check Eligibility and Configure OneDrive Storage Limits

5-User Minimum Requirement: To be eligible for 5 TB or up to 25 TB of OneDrive storage per user, your tenant must have a minimum of five qualifying Microsoft 365 E3, E5, or SharePoint Plan 2 licenses assigned. Tenants with fewer than five users are capped at 1 TB per user.

Solution 2

Review Exchange Online and SharePoint Storage Allocations

Understand the default capacities provided for Exchange Online Plan 2 and SharePoint Plan 2 included in Microsoft 365 E3.

Free Microsoft Office alternative

Looking for a Cost-Effective Office Suite with Built-in Cloud Storage?

If managing expensive enterprise licenses and complex storage tiers like Microsoft 365 E3 is becoming burdensome, consider WPS Office. It provides a lightweight, highly compatible alternative with familiar interfaces, built-in cloud capabilities, and seamless document management for teams without the enterprise-level overhead.

Fully compatible with Microsoft Word, Excel, and PowerPoint formats (.docx, .xlsx, .pptx).Integrated WPS Cloud storage for seamless file syncing and team collaboration across devices.Free to download and use with a lightweight installation and low system requirements.All-in-one interface allows you to manage documents, spreadsheets, and PDFs in a single tabbed window.

microsoft office alternative - wps office

Frequently Asked Questions

Do I need 5 users to get more than 1 TB of OneDrive storage in Microsoft 365 E3?

Yes. Microsoft requires a minimum of five users assigned to qualifying licenses (like Microsoft 365 E3 or E5) to increase the OneDrive storage limit from the default 1 TB to 5 TB or up to 25 TB.

What happens to a user's mailbox when it reaches the 100 GB limit?

Once the primary mailbox reaches 100 GB, the user will be unable to send or receive new emails. Administrators should enable auto-expanding archiving (In-Place Archive) to provide additional space before the limit is reached.

Can I purchase additional SharePoint storage if my tenant runs out?

Yes. If your organization exceeds the default SharePoint storage allocation (1 TB + 10 GB per licensed user), you can purchase additional storage capacity on a per-gigabyte basis through the Billing section of the Microsoft 365 Admin Center.

Login & Account Issues