About chmod Calculator
The chmod (change mode) command in Unix/Linux sets file and directory permissions. Permissions are expressed in octal notation (e.g., 755) or symbolic notation (e.g., rwxr-xr-x). Each digit in the octal format represents permissions for the owner, group, and others, where read=4, write=2, and execute=1. This calculator converts between all formats instantly.
How to Use
Toggle the read, write, and execute checkboxes for owner, group, and others to build your permission set. The octal value, symbolic notation, and chmod command update in real time. You can also type an octal value (e.g., 644) to set the checkboxes automatically. Copy the result in any format with one click.
Common Use Cases
- •Setting correct permissions for web server files (644 for files, 755 for directories)
- •Configuring SSH key file permissions (600 for private keys)
- •Making shell scripts executable (chmod +x equivalent)
- •Understanding permission errors in deployment environments
- •Teaching or learning Unix file permission concepts