File Type Detector

About File Type Detector

This tool detects the actual file type by analyzing magic bytes (file signatures) rather than relying on file extensions. Upload any file to discover its true MIME type and recommended extension. Useful for verifying file authenticity, detecting renamed files, or identifying unknown files. All processing happens in your browser for complete privacy.

What are magic bytes?

Magic bytes (or file signatures) are specific byte sequences at the beginning of files that identify the file format. For example, JPEG files start with FF D8 FF, PNG files with 89 50 4E 47. This tool reads these signatures to determine the actual file type.

Why detect file type by magic bytes?

File extensions can be changed easily, but magic bytes cannot be faked without corrupting the file. This tool helps: verify file authenticity, detect files with wrong extensions, identify renamed files, and discover the true format of unknown files.

What does 'Type Mismatch' mean?

A type mismatch means the file extension doesn't match the actual file content. For example, a .jpg file that's actually a PNG image. This could indicate a renamed file or potential security risk.

What file types can be detected?

The tool can detect hundreds of file types including images (JPEG, PNG, GIF, WebP), videos (MP4, AVI, MKV), audio (MP3, WAV, FLAC), documents (PDF, DOCX), archives (ZIP, RAR, 7Z), and many more.

What if the file type is unknown?

If the tool shows 'Unknown or unsupported file type', the file either uses a rare format not in the library's database, is corrupted, or is a plain text file (which has no magic bytes).

Can this detect malware?

This tool only detects file format, not malicious content. However, it can help identify files disguised with wrong extensions (e.g., an executable pretending to be an image), which is a common malware technique.

Is my file uploaded to a server?

No! All file type detection happens directly in your browser by reading the first few bytes. Your file never leaves your device and is never uploaded.

Why does my text file show as unknown?

Plain text files (.txt, .csv, etc.) don't have magic bytes - they're just text. The tool can only detect file types that have specific binary signatures at the start of the file.