.WOFF file signature
A Web Open Font Format file begins with the bytes 77 4F 46 46 (wOFF in ASCII) at the start of the file. The signature is the same whatever the file is named, which is why a renamed or extensionless WOFF file is still recognisable.
Signature
| Offset | Hex | ASCII |
|---|---|---|
| 0 | 77 4F 46 46 | wOFF |
MIME type: font/woff · usual extensions: .woff
How to check a file's signature
Without installing anything: drop the file on our detector. It reads the bytes in your browser and shows the hex dump alongside the verdict; nothing is uploaded.
macOS and Linux (Terminal):
xxd -l 32 file.woff
file file.woffWindows (PowerShell):
Format-Hex -Path file.woff -Count 32If the bytes do not match
A file named .woff whose first bytes are something else is not a WOFF file. The common explanations are a wrong or deliberately misleading extension, a download that saved an HTML error page instead of the file, or a container such as ZIP wrapping the real content. The detector reports what the bytes say; the WOFF guide explains what a genuine file should contain.