Free Chmod Calculator

chmod 755 gives the owner full permissions (read, write, execute = 7), while the group and others get read and execute permissions (5). This is the most common permission for directories and executable scripts, allowing the owner to modify files while letting others access them.

Unix permissions control who can read (r=4), write (w=2), and execute (x=1) files. Each permission has a numeric value, and you add them up for each role: Owner, Group, and Others. For example, read+write = 6, read+execute = 5, and read+write+execute = 7.

Numeric notation uses three digits (e.g., 755) where each digit represents permissions for owner, group, and others. Symbolic notation uses letters like rwxr-xr-x where r=read, w=write, x=execute, and - means no permission. Both represent the same permissions in different formats.

Use 644 for regular files (like HTML, CSS, images) where the owner can read and write, but others only need to read. Use 755 for directories and executable files (like scripts) where the execute permission is needed to enter directories or run scripts.

chmod 777 gives everyone full read, write, and execute permissions, which is a security risk on multi-user systems or web servers. It should generally be avoided in production. Use more restrictive permissions like 755 for directories or 644 for files instead.