File Type Checker
Identify a file from its magic bytes, not just its name or extension.
Quick answer: enter your details below and click Check File Type — your result appears instantly, right here in your browser. Nothing you enter is uploaded or stored.
F
Converters & Utilities
Enter your details below.
How to use
- Choose a file in the browser.
- Click Check File Type.
- Read the detected type from the magic bytes.
- Compare it with the extension to spot a renamed file.
About this tool
A file extension can be renamed in a second, but the opening bytes of a file, its magic signature, are much harder to fake by accident. This checker reads those first bytes in the browser and matches them against known signatures for PNG, JPEG, GIF, PDF, ZIP, and MP3 files. Everything happens locally, so the file itself is never uploaded for inspection.
Frequently asked questions
Why check magic bytes instead of the extension?
Extensions are just part of a name and can be changed freely, while magic bytes describe what the file actually starts with.
What if the type comes back unknown?
It means the opening bytes did not match the six signatures this tool knows, not that the file is broken.