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Chmod Calculator

Convert between numeric and symbolic Unix file permissions

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About Chmod Calculator

Convert Unix file permissions between numeric (e.g., 755) and symbolic (e.g., rwxr-xr-x) notation. Auto-detects input format.

How It Works

Numeric permissions use three octal digits (0-7) representing owner, group, and others. Each digit is the sum of read (4), write (2), and execute (1) permissions. The tool converts between numeric and rwx string representations.

Step by Step

  1. 1 Enter a numeric permission (e.g., 755) or symbolic (e.g., rwxr-xr-x)
  2. 2 The tool auto-detects the format and converts to the other
  3. 3 View the permission breakdown for owner, group, and others

Tips

  • 755 is the standard permission for executable files and directories
  • 644 is the standard for regular files (owner read/write, others read-only)
  • 600 makes a file readable and writable only by the owner (good for SSH keys)

Frequently Asked Questions

What does each digit mean?
The three digits represent owner, group, and others. Each is a sum of read (4), write (2), and execute (1).
What is the most restrictive permission?
000 removes all permissions. 400 is read-only for the owner, commonly used for sensitive files.