Understanding Exchange Online Plan 2 Licensing and Its Impact on Microsoft 365 Mailbox Features

Microsoft 365 (M365) offers a wide range of licensing options, and many users are unsure how individual service plans—such as Exchange Online Plan 2—interact with existing Microsoft 365 subscriptions like Business Basic. This article explains how Exchange Online Plan 2 works, whether Microsoft Teams is included, and what happens to mailbox storage when combining licenses.

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Can You Assign Exchange Online Plan 2 Directly to a Microsoft 365 Mail Account?

Yes. Exchange Online Plan 2 can be assigned directly to any user in the Microsoft 365 Admin Center. This plan enhances that user’s mailbox capabilities by providing advanced email features, including:

• 100 GB primary mailbox

• Archive mailbox

• Auto-expanding archive (up to ~1.5 TB)

• Advanced compliance features such as retention policies and DLP

Important Licensing Notes

• If the user already has a license that includes Exchange Online (for example, Business Basic or Office 365 E1), then you must ensure there are no conflicting Exchange plans. Often this means disabling the Exchange Online component of the previous license.

• You do not need a full Microsoft 365 suite license to assign Exchange Online Plan 2—this can be purchased independently.

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Does Exchange Online Plan 2 Include Microsoft Teams?

No — Microsoft Teams is not included with Exchange Online Plan 2.

Exchange Online Plan 2 only provides email-related features. To access Teams, a user must have one of the following licenses:

• Microsoft 365 Business Basic

• Microsoft 365 Business Standard

• Microsoft 365 Business Premium

• Office 365 E1 / E3 / E5

• Microsoft 365 E3 / E5

If a user only has Exchange Online Plan 2, they will not be able to sign into Teams.

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Mailbox Storage: Business Basic + Exchange Online Plan 2

Many users wonder whether combining Business Basic (which includes a 50 GB mailbox) with Exchange Online Plan 2 (which includes a 100 GB mailbox) results in:

✔️ 150 GB mailbox or ✔️ 100 GB mailbox or ✔️ something else entirely?

Correct Answer: The mailbox becomes 100 GB, not 150 GB.

Here’s why:

License Component	Mailbox Size
Business Basic (default)	50 GB
Exchange Online Plan 2	100 GB
Archive Mailbox	Enabled (Auto-expanding up to ~1.5 TB)

When Exchange Online Plan 2 is assigned, its mailbox limits override the smaller mailbox included in Business Basic. You do not “stack” sizes—Microsoft uses the highest available mailbox capacity from any assigned license.

What About 150 GB?

150 GB active mailbox is only possible in certain Enterprise plans (E3/E5) with the appropriate archive configuration. It does not apply to Business Basic + EOP2.

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Summary

Feature	Exchange Online Plan 2	M365 Business Basic	Combined
Primary Mailbox Size	100 GB	50 GB	100 GB
Archive Mailbox	Yes	Yes	Yes (up to ~1.5 TB)
Microsoft Teams	❌ No	✔️ Yes	✔️ Yes (Business Basic adds Teams)
Email Advanced Features	✔️ Advanced	Basic	✔️ Advanced

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Final Recommendation

If you want a user to:

• Have a 100 GB mailbox

• Use Teams

• Get archive mailbox features

• Use Microsoft 365 cloud services

Then assign:

✔️ Microsoft 365 Business Basic

+

✔️ Exchange Online Plan 2

This combination gives the user both Teams access and enhanced mailbox capabilities.