How to Check if You Are Running a 32-bit or 64-bit Version of Firefox

Firefox is available in both 32-bit and 64-bit versions for Windows 7, 8, and 10. If you’re curious which version you’re running, we’ll show a couple of easy ways to find out.

Using the About Firefox Box

The simplest method for finding this information is opening the About Firefox box. However, before continuing, be aware that opening the About Firefox box causes Firefox to automatically update, if there’s an available update. So, if you’d rather not update Firefox right now, skip to the next section for another easy method.

To check if Firefox is 32-bit or 64-bit using the About Firefox box, click the Firefox menu in the upper-right corner of the window and then click the Help icon at the bottom of the menu.

On the Help pane that slides out, click the “About Firefox” option.

If you’re running a 32-bit version of Firefox, it will say “(32-bit)” next to the version number on the About Mozilla Firefox box.

Otherwise, you will see “(64-bit)” next to the version number.

Using the Troubleshooting Information Page

If you don’t want Firefox to automatically update right now, you can check whether Firefox is 32-bit or 64-bit on the Troubleshooting Information page. To do this, click the Firefox menu in the upper-right corner of the window and then click the Help icon at the bottom of the menu.

On the Help pane that slides out, click the “Troubleshooting Information” option.

The Troubleshooting Information page displays on a new tab. Look at the “User Agent” section under Application Basics. If it says “WOW64”, you’re running the 32-bit version of Firefox.

If it says “Win64”, you’re running the 64-bit version.

If the User Agent section on the Troubleshooting Information page doesn’t say either “WOW64” or “Win64”, then you’re running a 32-bit version of Windows, and you cannot run a 64-bit version of Firefox.

If you use Chrome, you can also check whether you are running a 32-bit or 64-bit version of Chrome.

Lori Kaufman is a writer who likes to write geeky how-to articles to help make people's lives easier through the use of technology. She loves watching and reading mysteries and is an avid Doctor Who fan.