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Chmod Calculator

Calculate Linux/Unix file permissions visually. Convert between octal (755) and symbolic (rwxr-xr-x) notation instantly.

Guide: How to use & features

  • Select permissions for "Owner", "Group", and "Others" using the checkboxes.
  • The corresponding chmod command is generated in real-time in the output area.
  • You can also input an octal number to see the matching visual permissions.

Samples: Sample input & output

Calculate 755 (rwxr-xr-x)

Input

Owner: Read, Write, Execute
Group: Read, Execute
Others: Read, Execute

Output

chmod 755

FAQ: Frequently asked questions

  • What do numbers like "755" or "644" mean?

    They represent permissions for Owner, Group, and Others. For example, 7 is the sum of Read (4) + Write (2) + Execute (1).

  • Does it support Sticky bit or SUID?

    Currently, it supports basic 3-digit permission settings. Specialized bits are planned for future updates.

  • What happens if I set wrong permissions?

    You might lose access to files or fail to execute scripts. We recommend verifying with this tool before applying.

Use cases: Common use cases

  • Server setup permissions

    Quickly calculate recommended permissions for web directories and sensitive files.

  • Debugging access issues

    Visually match current octal values against intent to fix "Permission Denied" errors.

  • Security auditing

    Double-check if permissions are too loose (like world-writable) on a clean GUI.

Notes: Notes & limitations

  • Root Privileges

    Modifying system file permissions may require sudo. Pay attention to your execution environment.

  • Security Risks

    Setting open permissions like "777" can be a security risk. Use the most restrictive permissions necessary.
chmod 755 filename
Copied!
Owner Group Public
Read (4)
Write (2)
Execute (1)

Special Bits

chmod Permission Calculator

Linux file permissions can be written as numeric modes such as 755, symbolic values such as rwxr-xr-x, or chmod commands. This calculator helps translate between permission formats so you can review access before applying it to scripts, files, or directories.

Common use cases

  • Understand numeric modes: Translate 644, 755, 600, and similar values into readable permissions.
  • Review deployment commands: Check chmod values before changing server files.
  • Explain permissions: Share clear owner, group, and others permission details in documentation or tickets.

Security note

Avoid broad permissions such as 777 unless you fully understand the environment and risk. Write access for everyone can create serious security problems on shared systems.

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