Chmod Calculator

About Chmod Calculator

Chmod Calculator helps you understand and generate Unix/Linux file permission codes. File permissions control who can read, write, or execute files on unix-based systems.

How It Works

Unix permissions are divided into three groups: owner, group, and others. Each group can have read (4), write (2), and execute (1) permissions. The octal notation sums these values for each group, resulting in a three-digit number.

Common Use Cases

• Web server files (typically 644 for files, 755 for directories)
• SSH keys (600 for private keys)
• Deploying applications with correct executable permissions
• Troubleshooting permission-denied errors

Tip: Check or uncheck the permission boxes to see the octal and symbolic notations update in real-time. You can also enter an octal value directly.