About
File Formats is a reference for every kind of file: what each format is for, the software that opens it, and how its bytes are laid out.
How the site is organised
Formats are filed by what they are for: Audio, Video, Images, 3D & CAD, Documents, Data, Code and System. Each category is split into groups, and each group lists its formats. A format’s overview gives its extension and full name, an introduction, the main software that opens it and a summary of its structure. Formats with a full reference have a page for each part of the file, listed in the menu beside the overview.
One extension can mean more than one format. A .exe file can be an MS-DOS
program, a 16-bit Windows program or a modern Windows program, and .obj is
both a 3D model and a compiled object file. Each of these has its own page, and the
See also list at the foot of each overview links to the others.
Looking inside a file
Drop a file on any page, or choose one from the home page, and it opens in a hex viewer: the file’s offsets, bytes and text side by side, with the selected bytes read as numbers underneath. The site names the format when it recognises it and links to its reference. The file is read in your browser, a piece at a time, and is never uploaded.
Corrections and suggestions
If something is wrong or missing, please get in touch.