File Type Checker
Find the real type of a file from its content. Free, no sign-up, files stay on your device.
Choose files to checkor drag and drop files here
🔒 100% private — processing happens in your browser. Nothing is uploaded.
How to use the file type checker
- Choose one or more files (the content is checked, not just the name).
- Read the detected type next to the file’s extension.
- If they don’t match, rename the file or treat it with care.
A file’s extension can be wrong or deliberately fake — a “photo.jpg” that is really a Windows program is a classic trick. Every file format starts with a recognisable signature (so-called magic bytes). This checker reads the first few kilobytes of each file and compares them with more than 50 known signatures: images, documents, archives, audio, video, fonts and executables. It is also useful when a download has no extension at all. Only the beginning of the file is read and nothing is uploaded.