This is a list of file formats organized by type, as can be found on computers. Filename extensions are usually noted in parentheses if they differ from the format name or abbreviation. In theory, using the basic Latin alphabet (A–Z) and numerals (0-9), a three character extension can yield up to 46,656 combinations; (26+10)3.
When other acceptable characters are accepted, the maximum number is
increased (very possibly to a number consisting of at least six digits).
Many operating systems do not limit filenames to a single extension
shorter than 4 characters, as was common with some operating systems
that supported the FAT file system. Examples of operating systems that do not impose this limit include Unix-like systems. Also, Microsoft Windows NT, 95, 98, and Me do not have a three character limit on extensions for 32-bit or 64-bit applications on file systems other than pre-Windows 95/Windows NT 3.5 versions of the FAT file system. Some filenames are given extensions longer than three characters.