File Type Checker
Find out what a file really is from its contents.
Results
| File | What it is | MIME type | Extension |
|---|
Thanks.Tell us why
Runs on your device. No upload wait.
Questions
How can a file be something other than its extension says?
The extension is just part of the name, and anyone can change it. The contents start with a signature (a “magic number”) that says what they really are: every PNG begins with the bytes 89 50 4E 47, every PDF with %PDF-. This tool reads that signature.
Why does a Word or Excel file show as a ZIP inside?
DOCX, XLSX, PPTX, EPUB, APK and JAR files are all ZIP archives with particular files inside. The checker looks at the names inside to tell them apart, and reports the specific type.
Is a file with the wrong extension dangerous?
Not necessarily: often it was just renamed, or saved by an app that picked the wrong name. But a “photo” that is really a Windows program is a classic trick, so be careful with a mismatch you didn’t expect.
Is it free? Do I need an account?
It is free to use and there is nothing to sign up for. There are no watermarks and no daily limits.
Missing something, or not working as it should? Tell us