Chmod Calculator — Unix File Permissions

Calculate Unix file permissions in octal and symbolic notation. Visual chmod calculator for Linux and macOS.

Octal Notation
755
rwxr-xr-x
chmod 755 filename
ReadWriteExecuteOctal
Owner7
Group5
Others5

Common Permissions

What is chmod?

chmod (change mode) is a Unix/Linux command that sets file permissions. Permissions control who can read, write, or execute a file. They are divided into three groups: owner, group, and others.

How Octal Notation Works

Each digit (0-7) represents a combination of read (4), write (2), and execute (1) permissions. For example, 7 = rwx (4+2+1), 5 = r-x (4+1), 0 = --- (no permissions). A common setting is 755, giving the owner full access and everyone else read + execute.

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