Maximum Number of Files in a Single Directory

Let’s break this down by file system:

• FAT aka FAT16

  FAT, for File Allocation Table, is the successor to the original FAT12 filesystem that shipped with MS-DOS many, many years ago.

  • Maximum disk size: 4 gigabytes

  • Maximum file size: 4 gigabytes

  • Maximum number of files on disk: 65,517

  • Maximum number of files in a single folder: 512 (if I recall correctly, the root folder "/" had a lower limit of 128).

• FAT32

  "There’s no practical limit on the combined sizes of all the files in a folder, though there may be limits on the number of files in a folder."

  FAT32 was introduced to overcome some of the limitations of FAT16.

  • Maximum disk size: 2 terabytes

  • Maximum file size: 4 gigabytes

  • Maximum number of files on disk: 268,435,437

  • Maximum number of files in a single folder: 65,534

• NTFS

  NTFS, or "New Technology File System" introduced with Windows NT, is a completely redesigned file system.

  • Maximum disk size: 256 terabytes

  • Maximum file size: 256 terabytes

  • Maximum number of files on disk: 4,294,967,295

  • Maximum number of files in a single folder: 4,294,967,295

Note that when I say "disk" above, I’m really talking about "logical" disks, not necessarily physical. No one makes a 256 terabyte disk drive, but using NTFS you can treat an array of disk drives as a single logical disk. Presumably if you have enough of them, you can build a huge logical drive.

Also note that the NTFS’s 256 terabyte limitation may well simply be an implementation restriction - I’ve read that the NTFS format can support disks up to 16 exabytes (16 times 1,152,921,504,606,846,976 bytes).