Exchange 2010 FAQ: Which Version of Exchange Server 2010 Do I Need?Question: Do I need to purchase the Standard Edition or the Enterprise Edition of Exchange Server 2010 for my organization?

Exchange Server 2010 is available in two editions; Standard or Enterprise.  The only difference between these two product editions is how many databases (of either mailbox or public folder type) it can host.

  • Exchange Server 2010 Standard Edition can host up to 5 databases
  • Exchange Server 2010 Enterprise Edition can host up to 100 databases

This makes selecting Exchange Server 2010 licenses fairly simple.

  • Use Exchange Server 2010 Standard Edition for all Client Access, Hub Transport, Edge Transport, and Unified Messaging servers
  • Use Exchange Server 2010 Standard Edition for Mailbox servers that require 5 or fewer databases
  • Use Exchange Server 2010 Enterprise Edition for Mailbox servers that require more than 5 databases

For Mailbox servers that are members of a Database Availability Group each passive copy of a database counts as a database on the server. So if a Mailbox server has 4 active mailbox databases and another 4 passive copies it will need to be running the Enterprise Edition of Exchange Server 2010.

However, Exchange 2010 Enterprise Edition is not required for DAG members that host 5 or fewer active and passive databases. A common misconception is that Enterprise Edition is required for Exchange high availability. This is not true, DAG members can run either Standard or Enterprise edition (even within the same Database Availability Group).

However all DAG members must run Enterprise Edition of Windows Server 2008 or 2008 R2, which is required for the underlying Failover Cluster that the DAG utilizes.

The edition of Exchange Server 2010 is solely determined by the product key that is entered after the server is installed.  When the server is running in 120 day trial mode (ie without a product key) it operates under the limits of Standard Edition.  A server can be upgraded to Enterprise Edition simply by entering the new product key.

You can read more about Exchange Server 2010 licensing on the Microsoft website:

About the Author

Paul Cunningham

Paul is a former Microsoft MVP for Office Apps and Services. He works as a consultant, writer, and trainer specializing in Office 365 and Exchange Server. Paul no longer writes for


  1. Garrett Michael Hayes

    I know this is an old post, but I’m hoping you can clarify a licensing point for me. If an organization fielded, say, 3 Exchange Standard servers, could they then host 15 databases? (Regardless of the advisability.)

    I’m wondering, because I have a 2 server DAG running 2010 Standard with 4 mailbox stores and Public. One of those stores is damaged and I *really* need to evacuate it to a new DB. But with the existing DBs I can’t create a new DB. I can license Enterprise if I need to, but that’s a heck of a tab for rebuilding one DB.

    What I was thinking of doing is spinning up another server with just the database role (not joining to the DAG) and create a new DB there. Then migrate the mailboxes over a few days. Finally, once everyone is moved, delete the evacuated DB and move the new DB over to the DAG server(s).

    Any thoughts?

    1. Avatar photo
      Paul Cunningham

      Yes, a Standard edition server can host up to 5 databases. 3 Standard edition servers could host up to 5 databases each.

      You could also consider just moving the mailboxes to an existing DB instead of building a whole new server.

      1. Garrett Michael Hayes

        Great suggestion – I would love to. Unfortunately [le sigh], the existing servers are physical boxes and don’t have enough room on the other volumes to handle the amount of data. I plan to build out the new server as a virtual box, so I can either decommission it after the move, or decide to make it a part of the infrastructure.

  2. Alex

    Thanks for sharing information about Exchanged Server 2010. It’s really very helpful and simple clarification. I am also using Exchange Server 2010 Standard Edition for Mailbox servers in my company.

  3. Eissa

    Thank you so much very simple and clarity explanation

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