Chmod Calculator
Calculate Unix file permission octal numbers (755, 644) and symbolic notation.
Chmod Permission Checkboxes
About Chmod Calculator
The Linux & Unix Chmod Permissions Calculator generates numeric Octal notation (e.g. `755`, `644`, `777`) and symbolic notation (`-rwxr-xr-x`) with interactive checkboxes for Read (r), Write (w), and Execute (x) permissions across Owner, Group, and Public/Others.
How to Use Chmod Calculator
Step 1
Check or uncheck the Read, Write, and Execute boxes for Owner, Group, and Others.
Step 2
View the computed 3-digit and 4-digit octal permission codes in real time.
Step 3
Copy the generated `chmod` terminal command.
Practical Use Cases for Chmod Calculator
Linux Server & VPS File Security
Set secure permissions on web servers (e.g. `644` for web files, `755` for directories, `400` for SSH private keys `id_rsa`).
CI/CD Pipeline & Script Execution
Add execute permissions to bash deployment scripts with `chmod +x script.sh` or `chmod 755`.
Input & Output Examples
Setting Standard Web Directory Permissions (755)
Owner: Read+Write+Execute (7), Group: Read+Execute (5), Others: Read+Execute (5)
Octal: 755 | Symbolic: rwxr-xr-x | Command: chmod 755 /path/to/directory
Key Features & Performance
- ✓Interactive visual permission grid: Owner (User), Group, and Others/Public.
- ✓Real-time conversion between Octal (755) and Symbolic (`rwxr-xr-x`) notation.
- ✓Special permissions support: SUID (SetUID), SGID (SetGID), and Sticky Bit.
- ✓Generates ready-to-run Linux/macOS terminal `chmod` commands.
- ✓100% Client-Side computation.
- ✓1-Click Copy chmod command.
Key Terminology & Definitions
Octal Permission Values
Numeric values assigned to permissions: Read = 4, Write = 2, Execute = 1. The sum of these values creates the digit (e.g. 4+2+1 = 7).
Sticky Bit (1000 / t)
A permission bit on directories that allows only the file owner or root to delete or rename files within that directory (e.g. `/tmp` mode 1777).