Keeping track of the free space on your flash drive is important when you frequently use it to store movies, games, videos or other large files. The simplest way to check the space on any drive is to plug it into a Windows computer and check it from there. You can also check most flash drives on a Mac, as long as they're not formatted in the Windows NTFS file system.

Windows

Step 1

Plug the flash drive into an open USB port on your PC.

Step 2

Press "Windows-E" on the keyboard to open File Explorer or Windows Explorer.

Step 3

Right-click the listing for the flash drive in the left pane, then select "Properties."

Step 4

Select the "General" tab, and then check the numbers after "Free Space:" The first number shows the free space in terms of bytes, while the second number shows the free space in terms of megabytes or gigabytes.

Mac

Step 1

Plug the flash drive into an open USB port on your Mac.

Step 2

Click anywhere on the desktop to open a Finder window.

Step 3

Click the listing for the flash drive in the left pane under Devices.

Step 4

Press the space bar to open a Quick Look window that shows the drive details, including the amount of free space.