How to Find Out if Your Outlook Installation is 32-Bit or 64-Bit

Find your version so you can install compatible add-ons and plugins

Man on laptop

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While Outlook itself runs much the same whether you have the 32- or 64-bit version installed, it is critical that you know which you have when installing add-ons or plug-ins. The main difference is that the 64-bit version has more processing power and can handle more data.

Instructions in this article apply to Outlook 2019, 2016, 2013, 2010, and Outlook for Office 365. Outlook 2007 and older versions were available only in 32-bit versions.

Check If Your Outlook Is 32-Bit or 64-Bit (2013 and Later)

Outlook can tell you whether you have the 32-bit or the 64-bit version by following these steps. The steps below apply to Outlook 2019, 2016, 2013, and Outlook for Office 365. The process differs on Outlook 2010 and are in the next section.

  1. Select File > Office Account.

    Outlook 2016 File and Office Account menu selected
  2. Select About Outlook under the Product Information section on the right.

    Outlook 2016 About Outlook option selected
  3. At the top of the About Outlook window, you will see the Outlook version name, the version number, and the bit version installed, either 32-bit or 64-bit.

    Outlook 2016 About Outlook window with bit version displayed

Determine Bit Version for Outlook 2010

The 2010 version of Outlook has a slightly different interface from later versions. It's still just a couple of clicks to find out if Outlook 2010 is a 32-bit or 64-bit version.

Click File > Help. In the far right pane, under About Microsoft Outlook, you will find the version number and, in parenthesis, either 32-bit or 64-bit.

Outlook 2010 About Microsoft Outlook with bit version displayed

Outlook 32-Bit vs. Outlook 64-Bit

The version of Outlook you use is important when adding plug-ins. Outlook add-ons are designed to work with either 32-bit or the 64-bit versions; installing an incompatible add-on or plug-in can cause problems with your software.

For instance, older add-ons such as the Calendar Printing Assistant are only compatible with the 32-bit Outlook. Similarly, applications that integrate with Outlook using Messaging Application Programming Interface (MAPI) need to be 64-bit or the integration will fail.

The benefits of using 64-bit Outlook are in the ability to use Excel and other Office applications with 64-bit addressing, and the support for larger files and larger memory capacities than are allowed with the 32-bit version.