Find out which macOS your Mac is using

Is your Mac up to date with the latest version of the Mac operating system (macOS or OS X)? Is it using the version required by some product or feature? Which versions are earlier (older) or later (newer, more recent) than the version currently installed? To find out, learn which version is installed now.

If your macOS isn't up to date, you may be able to update to a later version.

From the Apple menu  in the corner of your screen, choose About This Mac. You'll see the macOS name, such as macOS Mojave, followed by its version number. If some product or feature requires you to know the build number as well, click the version number to see it.

This example shows macOS Mojave version 10.14 build 18A391.

These are all Mac operating systems, starting with the most recent. When a major new macOS is released, it gets a new name, such as macOS Mojave. And as updates that change the macOS version number become available, this article is updated to show the latest version of that macOS.

If your Mac is using an earlier version of any Mac operating system, you should install the latest Apple software updates, which can include important security updates and updates for the apps installed by macOS, such as Safari, iTunes, Books, Messages, Mail, Calendar, and Photos.

• Always use the macOS that came with your Mac, or a compatible newer version.
• Learn how to reinstall macOS from macOS Recovery.