.RAR file signature
A RAR archive data file begins with the bytes 52 61 72 21 1A 07 00 (Rar!... 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 RAR file is still recognisable.
Known signatures
| Offset | Hex | ASCII |
|---|---|---|
| 0 | 52 61 72 21 1A 07 00RAR 1.5 to 4.x. | Rar!... |
| 0 | 52 61 72 21 1A 07 01 00RAR 5.0 and later. | Rar!.... |
MIME type: application/vnd.rar · usual extensions: .rar
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.rar
file file.rarWindows (PowerShell):
Format-Hex -Path file.rar -Count 32If the bytes do not match
A file named .rar whose first bytes are something else is not a RAR 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 RAR guide explains what a genuine file should contain.