What is Chmod Calculator?

Chmod Calculator is a free online tool that converts between three representations of Linux file permissions: octal notation (0-7), rwx symbolic notation, and chmod command syntax. It helps Linux users quickly understand and apply correct file permissions without memorizing permission values.

How do I use Chmod Calculator?

Simply enter your permission value in any format: type an octal number (e.g., 755), rwx symbols (e.g., rwxr-xr-x), or a chmod command. The calculator instantly converts to the other formats. You can also adjust permissions using interactive controls to see real-time updates across all three formats.

What do the three digits in chmod mean?

The three digits represent permissions for owner, group, and others respectively. Each digit is calculated by adding: read (r)=4, write (w)=2, execute (x)=1. For example, 755 means owner has 7 (4+2+1 = rwx), while group and others have 5 (4+1 = r-x).

Does Chmod Calculator handle special permissions?

Yes, the tool supports special permission bits: setuid (4xxx), setgid (2xxx), and sticky bit (1xxx). These appear as a fourth digit before the standard three-digit permission set and are commonly used for directories and sensitive executables.

Is Chmod Calculator free?

Yes, this tool is completely free to use at tools.bkns.vn. No registration, subscription, or limitations—convert unlimited file permissions instantly.

Chmod Calculator - Free online tool

The Chmod Calculator works by translating between three representations of Linux file permissions. Each permission set consists of three digits or symbols representing read (r/4), write (w/2), and execute (x/1) permissions for the owner, group, and others. The tool accepts input in any format and automatically generates the corresponding values in the other two formats.

For example, entering octal value 755 instantly converts to rwxr-xr-x notation and generates the chmod 755 command. The reverse is equally true—input rwx notation and receive the octal value and chmod command. The calculator handles special permission bits including setuid (4), setgid (2), and sticky bit (1) for advanced use cases.

All calculations are performed client-side using JavaScript, meaning your data never leaves your browser. This approach ensures maximum privacy and allows the tool to work instantly without server latency.

Server Administration: Quickly set correct permissions on files and directories when managing web servers, databases, or application directories
Development Workflows: Apply proper permissions to scripts, configuration files, and deployment artifacts during development and CI/CD pipelines
Permission Troubleshooting: Diagnose permission-related errors by converting current permissions to understand what access is being granted
Security Auditing: Review and adjust file permissions across systems to ensure compliance with security policies and least-privilege principles
Learning Linux: Understand how Linux permission bits work by experimenting with different octal values and seeing the corresponding rwx notation

Role	Read (r)	Write (w)	Execute (x)
Owner
Group
Other

Chmod Calculator

How It Works

Common Use Cases

Frequently Asked Questions