Maximum Outlook PST size

What is the maximum PST size for Outlook 2003, 2007, 2010, & 2013

Outlook 2003 & 2007 has a default size limit of 20GB

Outlook 2010 & 2013 has a default size limit of 50GB

There’s a lot more detail about PST size limits and how to modify them on Microsoft’s website with the following KB article.
Please note that although you can push the maximum size, you will experience performance issues as you get closer to the limit.

What you can do to ensure best performance and stability of Outlook?

  1. Determine your PST file size currently.  Open account settings and in the DATA Files tab, highlight your PST file name and click “Open file location”.  You will see the file there and check the size of the file.  Best to check before and after to see your results.
  2. Delete mail from Outlook’s various folders you no longer need to keep.  Especially “Deleted Items” and “Sent Items” where it builds up and most peoples focus is on the Inbox.
  3. Once deleted messages and cleared from “Deleted Items”, you need to compact the  database.  This KB article from Microsoft shows how to compact and repair your Outlook PST database file.