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Chmod Calculator

Calculate Unix file permissions (chmod) in numeric and symbolic format

Owner
Group
Others
Read (4)
Read
Read
Read
Write (2)
Write
Write
Write
Execute (1)
Execute
Execute
Execute

Numeric Notation (Octal)

644

Symbolic Notation

rw-r--r--
chmod 644 filename
Owner: Read, Write
Group: Read
Others: Read
Common Permissions:
  • 644 (rw-r--r--) - Default file permissions
  • 755 (rwxr-xr-x) - Default directory permissions
  • 777 (rwxrwxrwx) - All permissions (not recommended)
  • 600 (rw-------) - Owner read/write only
  • 700 (rwx------) - Owner full access only

What is Chmod Calculator?

Calculate Linux/Unix file permissions with our free Chmod Calculator. Convert between symbolic notation (rwxr-xr-x) and numeric/octal notation (755) instantly. Essential for system administrators, DevOps engineers, and web developers configuring file permissions on Linux servers, web hosting, and cloud deployments.

How to Use Chmod Calculator

1

Toggle permission checkboxes for Owner, Group, and Others (Read, Write, Execute).

2

View the numeric (octal) permission value update in real-time.

3

Or enter a numeric value like 755 to see the symbolic representation.

4

Copy the chmod command ready for your terminal.

Key Features

Interactive permission checkboxes
Instant octal to symbolic conversion
Common permission presets (644, 755, 777, etc.)
Generated chmod command ready to copy
Explanation of each permission level

Frequently Asked Questions

What does chmod 755 mean?

chmod 755 means: Owner has full permissions (read+write+execute = 7), Group has read+execute (5), and Others have read+execute (5). This is the standard permission for directories and executable scripts on web servers.

What is the difference between chmod 644 and 755?

644 (rw-r--r--) is for regular files - owner can read/write, others can only read. 755 (rwxr-xr-x) adds execute permission, needed for directories and scripts. Use 644 for HTML/CSS/PHP files and 755 for directories.

Why should I never use chmod 777?

chmod 777 gives everyone full read, write, and execute access, creating a serious security vulnerability. Any user or process on the system can modify or delete the file. Use the minimum permissions necessary for your use case.