Chmod Calculator
Calculate Linux file permissions in octal and symbolic format. Visual checkbox interface for easy permission management.
Linux Permissions
Octal Value
Symbolic Value
About Linux File Permissions
File permissions in Linux and Unix-like systems control who can read, write, and execute files and directories. Permissions are set for three categories of users: the file owner, the group, and others (public). Each category can have read (r), write (w), and execute (x) permissions, represented by the values 4, 2, and 1 respectively.
The chmod command uses octal notation (base-8) where each digit represents the permissions for owner, group, and others. For example, 755 means the owner has full permissions (7 = 4+2+1), while group and others have read and execute permissions (5 = 4+1). Symbolic notation like -rwxr-xr-x provides a human-readable representation of the same permissions.
Understanding file permissions is crucial for system security, especially on web servers and shared hosting environments. Incorrect permissions can lead to security vulnerabilities or prevent legitimate access to files. Our calculator helps you visualize and calculate the correct permissions for your use case.