The best Mac OS version is the one that your Mac is eligible to upgrade to. In 2021 it is macOS Big Sur. However, for users that need to run 32-bit apps on Mac, the best macOS is Mojave. Also, older Macs would benefit if upgraded at least to macOS Sierra for which Apple still releases security patches.

What OS can I run on my Mac?

Mac OS Compatibility Guide

• Mountain Lion OS X 10.8.x.
• Mavericks OS X 10.9.x.
• Yosemite OS X 10.10.x.
• El Capitan OS X 10.11.x.
• Sierra macOS 10.12.x.
• High Sierra macOS 10.13.x.
• Mojave macOS 10.14.x.
• Catalina macOS 10.15.x.

What OS can I upgrade my Mac to?

Before you upgrade, we recommend that you back up your Mac. If your Mac is running OS X Mavericks 10.9 or later, you can upgrade directly to macOS Big Sur. You’ll need the following: OS X 10.9 or later.