WOFF2 file signature
Magic number at the start of the file · wOF2
Web Open Font Format 2 files begin with the tag wOF2. The earlier WOFF 1.0 uses wOFF. Both wrap an sfnt font with web-optimised compression, Brotli for WOFF2 and zlib for WOFF.
What this magic number means
A magic number is a short, fixed run of bytes at a known position that tells a program what a file really is, no matter what the filename says. If a file starts with the bytes 77 4F 46 32 (the text wOF2), it is a WOFF2 file.
Signature variants
WOFF2 appears with more than one byte pattern. These all identify the same family:
| Hex signature | Offset | Note |
|---|---|---|
| 77 4F 46 32 | 0 | WOFF 2.0 (Brotli-compressed) |
| 77 4F 46 46 | 0 | WOFF 1.0 (zlib-compressed) |
Formats that use the 77 4F 46 32 signature
These file types in our database carry this signature:
How to check a file's signature
You can read the first bytes of any file yourself. The magic bytes are shown in hex, the same way this page lists them.
Linux & macOS
- xxd -l 16 example.woff2
- hexdump -C -n 16 example.woff2
- file example.woff2
Windows (PowerShell)
- Format-Hex -Path example.woff2 -Count 16
Python
- open("example.woff2","rb").read(4).hex()
In your browser
- Drop the file into the WhatFileType identifier, which reads the signature without uploading it.
Frequently asked questions
What is the WOFF2 file signature?
WOFF2 files start with the hex bytes 77 4F 46 32 (wOF2 in ASCII). This magic number identifies the format regardless of the file's name or extension.
How do I check a file's magic number?
Open the file in a hex editor, or run a command such as xxd -l 16 example.woff2 on Linux or macOS, or Format-Hex -Path example.woff2 -Count 16 in Windows PowerShell, and read the first bytes.
Can a file fake the WOFF2 signature?
Renaming a file does not change its bytes, so the extension can lie but the signature usually cannot. A genuine WOFF2 file has these exact bytes; a file with the wrong bytes is not really WOFF2, whatever its name says.