How to use this encyclopedia
Each entry answers the same five questions: what the format is, what it does well, what it does badly, which programs open it and how to convert it when the recipient needs something else. A facts table at the top lists the extension, MIME type, developer, release year, licensing status and compression type so you can compare formats at a glance.
Entries link to each other where formats compete, such as JPG against PNG and WebP, or ZIP against 7Z, and to the converters that handle them. If you have a file whose type you cannot identify, the File Format Identifier reads its signature and tells you what it really is.
Choosing between formats
The right format depends on what happens to the file next. A document that must look the same everywhere travels as PDF; one that will be edited stays DOCX or ODT. A photograph is a JPG or HEIC on a phone and a WebP on a website; a screenshot or logo is a PNG or SVG. An archive for a stranger is a ZIP; one for your own backups can be a smaller 7Z.
When the file you have is not the file you need, the converters do the work: PDF tools for documents, image converters for pictures, video and audio converters for media, and archive tools for compressed files.