What Version of Firefox Do I Have
See which Firefox version your browser reports, read from your user agent.
Read from your browser's user agent string. Nothing is sent to a server; this is read and shown entirely in your browser.
What is What Version of Firefox Do I Have?
Reads the Firefox version straight out of your browser's user agent string — a quick check without digging through the hamburger menu → Help → About Firefox. Useful when you need to confirm compatibility with a site, report a bug against a specific build, or check whether an extension needs a newer release than the one you're running. The check runs entirely in your browser: nothing about your version or user agent is sent to a server. That also means it's only as reliable as what Firefox itself reports — modern Firefox still exposes its full version by default, but that could change as browsers move toward more privacy-preserving user agents, the way some other browsers already have.
FAQ
Either you're not using Firefox, or your browser sends a generic user agent for privacy, which is increasingly common.
Open the menu (☰) → Help → About Firefox. Firefox checks for updates automatically and will show a button to restart and apply one if it's already downloaded it.
No. The version is parsed from `navigator.userAgent` locally in JavaScript and never leaves your device.