DevToolKits.app
DevToolKits

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

Recent Articles

Story
2026-03-09

Generating QR Codes: Faster and Safer

Using Canvas API and node-qrcode to achieve real-time generation and privacy protection entirely within the browser.

Read more →
Story
2026-03-09

Solving JSON to TypeScript via Recursion: The Strength of Zero Dependencies

Generate type definitions instantly from API responses. A behind-the-scenes look at a lightweight, high-speed implementation using recursive algorithms.

Read more →
Story
2026-03-09

Secure JWT Verification in the Browser: A Security Engineer's Perspective

Handling sensitive tokens safely. Why we used the 'jose' library and local processing for our JWT tool design.

Read more →
Story
2026-03-09

Safe Without Data Transmission: The Background of Our Browser-based Diff Tool

How we designed a private, high-speed text comparison tool using browser-side computing to prioritize user privacy.

Read more →
Story
2026-03-09

Library-Free Timezone Conversion: The Power of Intl API

The story behind a lightweight timezone processing tool implemented using only the browser's native Intl API, without Moment.js or date-fns.

Read more →
Story
2026-03-03

The Story Behind SQL to ER Diagram: A Commitment to Browser-only Execution

Discover the background of our SQL-to-ER tool and the technical challenges of balancing security with convenience.

Read more →

Ad

Quick links to other tools

Stay within DevToolKits with shortcuts to the most-used utilities across the site.

DevToolKits.app
Articles
1 items
Article Index →
Development & DevOps
8 items
GitHub Actions Visualizer → SQL Formatter → Visual SQL Builder → SQL → ER Diagram → Curl Converter → Chmod Calculator → Cron Editor & Parser → Infrastructure Diagram Builder →
Data Conversion & Schemas
6 items
JSON Formatter → JSON → TypeScript → JSON → Zod → JSON → OpenAPI → JSON ⇔ YAML → CSV ⇔ JSON Converter →
Security & Cryptography
5 items
Base64 / 58 / 32 → JWT Tool → Hash & HMAC Generator → JWKS Generator → UUID Generator →
Text & Code Helpers
4 items
Markdown Table Generator → Text & Code Suite → Regex Tester → Diff Viewer →
URL & Network
4 items
URL Encode / Decode → URL Params → JSON → QR Generator → QR Reader →
Design & UI
2 items
Color Utility → Favicon Generator →
Date & Time
3 items
Time Zone Converter → Time Units → UNIX Timestamp Converter →

Ad