File Type Identifier

Got files with no extension, or with the wrong one? Drop them here – as many as you like, folders too – and the tool tells you for each file what it really is: the type, the usual extension, the MIME type and a short description.

It looks at the content, not the name: most formats start with a fixed signature ("magic bytes"), and containers are looked into, so a ZIP is told apart from a Word document, an Android app or an e-book, an MP4 from a MOV or HEIC photo, and an old .doc from an .xls or .msi. Over 300 formats are recognised: archives (RAR, ZIP, 7z, gzip, tar, …), pictures, audio, video, documents, programs, fonts, databases and disk images. Text files get a best guess (JSON, CSV, HTML, scripts, …); unknown files show their first bytes.

With one click you can save a copy of a file under its right name. Everything happens in your browser: only the first and last few KB of each file are read, and nothing is uploaded.