File Signature Checker
Inspect file magic bytes and compare them against known format signatures. This tool reads the opening bytes of a file directly in your browser to help identify likely formats and detect suspicious mismatches.
Upload a file to inspect its signature
This tool reads the opening bytes of your file and compares them with known magic byte signatures.
Drag and drop your file here
or
Supports common document, image, archive, audio, video, and executable formats.
File overview
Basic metadata and browser-reported information.
No file inspected yet. Upload a file to check its signature.
Signature result
Known matches based on the file header bytes.
Upload a file to compare its header with known signatures.
Raw header bytes
The first bytes of the file in hexadecimal and ASCII form.
Upload a file to inspect its header bytes.
What are file signatures?
File signatures, also called magic bytes or magic numbers, are the opening bytes of many file types. They often reveal the true file format even if the filename or extension has been changed.
What this tool checks
This checker reads the first bytes of your file, displays them in hexadecimal and ASCII form, and compares them with a set of known signatures for common formats such as PDF, PNG, JPEG, ZIP, RAR, EXE, GIF, and more.
It is useful for verifying downloads, inspecting renamed files, and checking whether a file header looks consistent with the format you expect.
Private and browser-based
The file stays on your device while the signature is checked in your browser. No upload is required, so the tool is useful for quick local inspection of documents, images, archives, media, and executable files.