Unix Permissions (chmod) Calculator

About this calculator

This tool translates a Unix/Linux file permission mode — written as a 3-digit octal number like 755 — into its readable rwx (read, write, execute) form, showing exactly what the owner, group, and everyone else (others) are allowed to do with the file, since each octal digit encodes a combination of those three permission bits.

System administrators, developers deploying a web server, and anyone running chmod on a Linux or macOS terminal use this to avoid guessing what a permission number actually grants — setting a file to 777 makes it writable and executable by literally anyone on the system, which is rarely what you want, while 644 is the safe default for a regular file and 755 for a script or directory. It's a quick way to translate between the octal shorthand used in commands and the rwxrwxrwx notation shown by ls -l.