What Version of macOS Do I Have
See which macOS version your browser reports, read from your user agent.
Nothing is sent to a server; this is read and shown entirely in your browser.
Need the opposite? What Operating System Do I Have
What is What Version of macOS Do I Have?
Reads the macOS version straight out of your browser's user agent string, a quick check without opening the Apple menu → About This Mac → System Settings. Useful for confirming compatibility before installing software, or for including your OS version in a support request or bug report. The check happens entirely client-side: your browser exposes an OS version in its user agent, this page parses it with JavaScript, and nothing is sent to a server. Note that macOS's user agent string has historically lagged behind the actual OS release in some browsers (showing an older major version number even after an update), so treat this as a strong hint rather than an authoritative source: About This Mac is always the ground truth.
How to Use This Tool
- 1
Open This Page on Your Mac: Visit this page in a browser on the device you want to check.
- 2
Read the Detected Version: The macOS version, parsed from the user agent string, appears automatically.
How It Works
macOS devices include a version token like `Mac OS X 10_15_7` inside `navigator.userAgent`, and this tool looks for that pattern and reads off the version. It's parsed entirely in your browser; nothing about your device is sent to a server.
Why This Might Be Wrong or Say "Unknown"
The version reported in a browser's user agent isn't always the actual macOS version installed. Some browsers cap the number they report, or update it slowly, which is why this can lag behind a real OS update. Beyond that lag, results can also be off because: you're not on a Mac at all; Safari (and browsers built on WebKit) has a long history of deliberately limiting or freezing version detail in its user agent for privacy; a browser is sending a different platform's tokens on purpose for site compatibility; or you're in an in-app browser from a social media app, which often reports a generic string. For the definitive version, check Apple menu → About This Mac directly.
Common Use Cases
Checking macOS compatibility before downloading software, or including your OS version in a support ticket or bug report without opening System Settings.
Frequently Asked Questions
Common questions about What Version of macOS Do I Have.