Where to find your Outlook version

The fastest way to check your Outlook version depends on which Outlook you use. Microsoft makes Outlook as a standalone desktop program (Outlook for Windows or Outlook for Mac), as part of Microsoft 365 subscriptions, and as a web version you access in your browser. Each one stores version information in a different place.

If you use Outlook on your computer, the version number lives in the About window. If you use Outlook on the web, it appears at the bottom of the screen. The steps take less than a minute either way.

Key Takeaways

  • Outlook for Windows shows its version in File > Account > About Outlook, displayed as a four-part number like 16.0.13127.20000.
  • Outlook for Mac displays the version under Outlook > About Outlook in the menu bar at the top of the screen.
  • Outlook on the web shows the version number at the bottom right corner of the screen, usually visible without clicking anything.
  • Microsoft 365 Outlook updates automatically, so your version number changes regularly unless you use a fixed release channel.
  • Knowing your version helps you troubleshoot problems, check if a feature is available, or confirm whether you need to update.

Checking Outlook version on Windows

Open Outlook and click the File menu in the top left corner. Then select Account from the left sidebar. You will see a button labeled "About Outlook" — click it, and a small window will pop up showing your version number.

The version appears as four numbers separated by periods, like 16.0.13127.20000. The first number (16) indicates you are using Outlook 2016 or newer. The other numbers track smaller updates and builds. Write down or screenshot this number if you need to reference it later.

If you use Outlook as part of Microsoft 365, you may also see "Microsoft 365" or "Office 365" displayed in this window. This tells you that your Outlook updates automatically rather than staying on a fixed version.

Checking Outlook version on Mac

Click Outlook in the menu bar at the very top of your screen, then select About Outlook from the dropdown menu. A window will appear showing your version number in the same four-part format as Windows (for example, 16.0.13127.20000).

On Mac, you may also see build information and the date the version was released. If you use Microsoft 365 on Mac, the About window will indicate that as well, meaning your version updates automatically.

Checking Outlook version on the web

Open Outlook in your web browser and look at the very bottom right corner of the screen. You will see a small line of text that includes the version number, usually displayed as a date or build identifier. This version updates automatically without any action from you.

The web version does not use the same four-part numbering system as the desktop versions. Instead, Microsoft identifies it by release date or build number. If you cannot see the version at the bottom right, scroll down to make sure you are viewing the entire page.

What the version number tells you

The first number in a desktop Outlook version (16, 17, or higher) corresponds to the year or generation of Outlook. Version 16 covers Outlook 2016 through current Microsoft 365 releases. Version 17 or higher indicates a newer generation.

The remaining three numbers track updates, security patches, and feature releases. A higher number means a more recent build. If you report a problem to Microsoft support or search for whether a specific feature exists in your version, having this exact number helps narrow down the answer.

Microsoft 365 subscribers receive updates automatically, so your version number will change every few weeks. If you use a standalone copy of Outlook (not part of a subscription), your version number stays the same until you manually run Windows Update or Mac Software Update.

Why you might need to know your version

Knowing your Outlook version helps in several situations. If you are troubleshooting a problem and contact Microsoft support, they will ask for your version number to determine whether the issue is a known bug in that build. If you are wondering whether a feature exists in your copy of Outlook, the version number tells you whether it is new enough to have it.

Version information also matters when you are deciding whether to update. If you use a standalone (non-subscription) copy of Outlook, you control when you update. Checking your current version tells you how far behind you are and whether security updates are available.

Frequently Asked Questions

Does Outlook automatically update, or do I have to update it myself?

If you use Microsoft 365, Outlook updates automatically in the background, usually every few weeks. If you use a standalone copy of Outlook (not part of a subscription), you must run Windows Update or Mac Software Update yourself to get new versions. You can check for updates manually through File > Office Account > Update Options on Windows.

What if I see a version number but it looks different from the four-part format?

Outlook on the web uses a different numbering system than the desktop versions and may show a date or build identifier instead. This is normal. If you are using the web version, that is the correct version number for your situation. Desktop versions (Windows and Mac) always use the four-part format.

Can I use an older version of Outlook, or do I have to update?

You can continue using an older version of Outlook if you own a standalone copy, but Microsoft eventually stops supporting very old versions. Microsoft 365 subscribers cannot stay on an old version — updates happen automatically. If you need to stay on a specific version, you can switch to a fixed release channel through your Microsoft 365 settings.

Where do I find the version number if I cannot open Outlook?

If Outlook will not open, you can check the version through Windows Settings or Mac System Preferences. On Windows, go to Settings > Apps > Apps & Features, search for Outlook, and click it to see the version. On Mac, open Applications, right-click Outlook, select Get Info, and look for the version number in the window that appears.

Is there a difference between the version number and the build number?

The version number and build number are related but not the same. The version number (like 16.0.13127.20000) includes the build number as part of it. The build number is typically the last two parts (13127.20000 in this example). Both refer to the same release, just in different levels of detail.