A file extension or filename suffix is usually three, four, or more characters at the end of computer file names, divided by a dot.
File extensions help users identify file types and formats when working with a computer file. Operating systems also use them to associate the file type with the appropriate application that opens the file.
For example, the file extension .txt tells your computer that the file is a text file and should be opened with a simple text editor, like Notepad on Windows or TextEdit on macOS.
file extension records in our database
Pick any file and find out what it really is: file format detected by its signature (magic bytes), HEX preview, checksums, text encoding, image and archive details – and a link to the matching file extension in our database with software that opens it.
Drag & drop a file here
or
The file never leaves your computer – everything is detected locally in your browser.
Optionally upload the file to our server for a deeper analysis: exact MIME type, metadata, archive inspection, entropy and a malware scan. Maximum size: 100 MB.
Check whether two files - even with different names - contain exactly the same data. Verify that a download matches a trusted copy, compare versions, or spot a renamed or potentially tampered file using size, type, and SHA-256. Everything runs locally in your browser; nothing is uploaded.
Language
