Check Mailbox Size In Outlook 2016


The maximum configurable rules quota is 256KB; which should cover about 100 rules.

For Outlook, the size of the mailbox is limited to the maximum size of the data file and is 50GB by default, but you can change this value if necessary (see the article). In order not to get confused in quotas on the mailboxes specified manually, it is recommended to use several databases with different quotas and, if necessary, to increase the. To check the space being utilized, click on ‘View Mailbox Size’ as shown in the image below: You can also empty the “Deleted Items Folder” or “Archive” your emails or even move mails to another outlook file, to free space. If your outlook needs to be reset due to errors you can follow our guide.


Here is the closest official reference I could find (the documentation for the Powershell cmdlet Set-Mailbox):

I couldn't find documentation specifically calling out this limit for the on-premises version of Exchange; but I did find a corroborating reference for a hard Exchange Online limit (which admittedly, isn't always the same):

This article share all information related to the size of Outlook OST File in Microsoft application. Here we discussed OST File Size Limitation in different Outlook version, it can be Outlook 2016/2013 & other old versions such as Outlook 2010 & 2007. We also explore the different method to check OST File size in Outlook and Find the solution question asked by different people related to the maximum size of an OST File in Outlook.

User Query Related to Exchange OST File Size Limit

Query 1: Hey, I am using Office Outlook 2010 version in my PC and Outlook 2013 version in the laptop. Some time use offline mode to store the local copy of Exchange Mailbox on the local machine. What is the maximum OST File size in Outlook 2010/2013 versions, Is size of file affect performance of my Outlook application.

Query 2: Recently installed Outlook 2013 in my system, and create an OST File to view Mailbox data Offline, but don’t know how to know how to check OST File size in Outlook 2013. Is there any size limit for OST file Is someone knows the method to examine the file size of Outlook OST File? Please share the method with me.

Query 3: What is the default size of OST File in Outlook 2010 application. Want to know Outlook OST file maximum size limit in Outlook 2010/2013 versions. Is there any difference in size of OST file of Outlook 2007 & upper version of Outlook like 2010.

Query 4: What is the Maximum OST File size limit in Outlook 2007/2010/2013 versions and is there any method, which can help me to check the size OST file locally stored in my system.

How to Configure Size of OST File in Different Outlook Version

Outlook uses two files to store information of user account, first is PST File used to store information while working online, whereas Offline storage file used to store data while user wants to work Offline or whether the internet is not available. Microsoft Outlook uses two formats to store file, one in UNICODE format, other one ANSI version, which is used in earlier version [2003 & old version] of Outlook.

An OST File created easily in Outlook version 2016 and other Outlook 2013, Outlook 2010 versions. To determine the Exchange OST File size limit in Outlook 2016/2013/2010/20017. Read the below section.

How to check OST File size in Outlook 2016/2013/2010/2007 Versions

In Outlook 2016 & Outlook 2013:

How To Check Mailbox Size In Outlook 2016

To check the size of OST File in Outlook 2016/2013, a user can navigate towards the local copy of OST File stored in Client version. Typical Location of Offline Storage File is defined below:


drive:Documents and Settings<username>Local SettingsApplication DataMicrosoftOutlook

For example -:C: Documents and Settings username Local Settings Application Data Microsoft Outlook outlook.ost

For Outlook 2010:Drive: Users%username%AppDataLocalMicrosoftOutlook

Check Mailbox Size In Outlook 2007

Outlook 2007: Drive: UsersuserAppDataLocalMicrosoftOutlook

Note: Position of OST File depend on Client versions or platform as well as Outlook versions.

A user can check the position of the file by the following instruction.

  1. Locate the Position of File from above location.
  2. After selecting the OST File, Click Right >> Select Data Properties option.

SimilarlyNow user can check the OST File is Outlook 2013/2010/2007 and other versions.

Default OST File size limit in Outlook 2003/2007 & Upper versions

As We already discussed that that default size of OST file can be varied according to versions of Outlook. O7 eve. Please view the below table to size capacity of OST File in different Outlook Versions.

Maximum File Size Limit of OST File in Different Outlook Versions

As there is no limit defined for the maximum size of Offline Storage Table File but technically storage capacity Outlook OST File is around 4194303GB or 4 PB. A user can increase OST file size limit using the different method. If a user still working on old ANSI format OST & PST File, then size limit is around 2 GB.

Note: Default size of OST File in Outlook is around up to 50 GB but which is presently the recommended limit of all versions of Outlook. AS Default OST File size limit in Outlook 2007 & below versions is around 20 GB and when the size of OST Mailbox increase, user start facing performance issues in Outlook application like unable to open the Outlook and messages related to deleting messages permanently. Outlook offers some registry entries, that can help users to increase size capacity of the offline file.


An OST File act as a local copy of Exchange mailbox, stored in the user system, when user not connected or working Offline. The file size of OST File can be issued, as for different Outlook Versions, the file size of OST File is defined. Exchange OST File Size for Outlook 2016/2013/2010/2007 is different than Outlook 2007 & below versions. A user can split OST File using different Splitter Tool that can easily break the File to avoid any performance issues arises due to the size of Exchange OST File.