A small number of PC users have installed 64-bit Firefox on 64-bit Windows 7/8/10, according to Mozilla. If you are running Windows 10/8/7 64-bit, it’s a good idea to upgrade Firefox 32-bit to 64-bit for better performance. If you are not sure if you have installed 32 or 64-bit Firefox, you can check the same by following directions mentioned in one of the given below methods. Following are the five ways to know if you are running 32-bit or 64-bit Firefox on Windows 10/8/7. Method 1 of 5 Check if you are running 32 or 64-bit Firefox Step 1: Launch Firefox. Press Alt key to see menus. Click Help menu and then click Troubleshooting information. Step 2: In the Application Basics section of the troubleshooting information page, look at the provided User Agent information. Step 3: A WOW64 entry indicates that you are running 32-bit Firefox. Win64; x64 will appear if you have installed Firefox 64-bit. Method 2 of 5 Use Settings to check if you are running 32 or 64-bit Firefox This method applies to Windows 10 only. Step 1: Open Settings. Click System > Apps & features. If you are on Windows 10 Creators Update (14997 or above build), navigate to Apps > Apps & features after opening System. Step 2: Locate Mozilla Firefox entry. As you can see in the picture below, the type (32 or 64-bit) of Firefox appears next to Mozilla Firefox entry. Method 3 of 5 Use Control Panel to check if you are running 32 or 64-bit Firefox Step 1: Type Appwiz.cpl in Start/taskbar search field and then press Enter key to open Programs and Features window. Step 2: Look for Mozilla Firefox entry. The program name includes the type of Firefox. As you can see in the picture below, I am running x86 (32-bit) version of Firefox on my PC. Method 4 of 5 Use Task Manager to find if you are running 32 or 64-bit Firefox Step 1: Run Mozilla Firefox, if not already running. Step 2: Open Task Manager. To do so, you can either use Ctrl + Shift + Esc hotkey or right-click on an empty spot on the taskbar and then click Task Manager. Step 3: If you see the stripped-down version of Task Manager, click More details. Step 4: Under Processes tab, the type (32-bit or 64-bit) appears next to Firefox’s name. Method 5 of 5 Find if you are running 32 or 64-bit Firefox using File Explorer Step 1: Open the drive where Windows 10 is installed. The drive where Windows 10 is installed displays Windows logo on it for easy identification. Step 2: Double-click on Program Files (x86) folder. Check if a folder named Mozilla Firefox folder is located under Program Files (x86) folder. The Mozilla Firefox folder under Program Files (x86) indicates that you are running a 32-bit version of Firefox unless you have both 32-bit and 64-bit installed. Hope this helps!