Chmod Calculator Icon

Master Unix Permissions

The deepest permissions learning tool on any platform. Exam simulation, cert prep, and interactive charts — coming in the next update. No subscription.

Learn the concepts. Practice with real exam formats. Track your mastery. Certification exam prep coming in the next update. Built for sysadmins, DevOps engineers, students, and developers.

One price. Runs on iPhone, iPad, and Mac.

Download on the App Store Learn More

Pro is currently $3.99 — increasing to $24.99 with v3.2. Lock in the introductory price now.

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📱 Scan to download on iPhone or iPad

QR Code to download Chmod Toolkit from App Store

See It In Action

Experience Chmod Toolkit on iPhone, iPad, and Mac

📱 iOS & iPadOS

↓ Download on App Store

💻 macOS

↓ Download on Mac App Store

One Goal: Mastery

Every feature serves one purpose — to take you from looking it up to knowing it cold. Calculate, learn, practice, and prove your knowledge.

🔢

Chmod Calculator

Interactive permission calculator with real-time numeric and symbolic conversion. Toggle between File and Directory modes for context-appropriate explanations.

🛡️

Security Scanner

Comprehensive permission analysis covering 24 security categories. Detect unsafe permissions, SSH keys, credentials, and configuration issues.

📚

Learn & Master

Searchable handbook with 20+ sections covering the 4+2+1 system, symbolic notation, user groups, and security best practices. Perfect for students and professionals alike.

🧠

Quiz System

Comprehensive quiz system across 5 question types with XP, levels, streaks, and spaced repetition. Track your progress with stats and achievements. Master permissions through practice.

📋

Smart Fix Commands

Automatically generated chmod commands to fix security issues. Copy individual fixes or generate batch scripts for multiple files.

⚡

Quick Fix

Paste terminal error messages and get instant fix recommendations. Recognizes 30+ common permission error patterns across Linux and macOS.

🔀

Permission Diff

Compare two permission sets side by side with a visual green/red grid. Instantly see what changed between current and target permissions.

🔖

Bookmarks & Special Bits

Save frequently used permission sets for one-tap recall. Full 4-digit support with setuid, setgid, and sticky bit toggles.

📊

CSV Export

Export scan results to CSV for professional audit reports. Perfect for compliance documentation and team collaboration.

🧩

Widgets & Shortcuts

Home screen and lock screen widgets for quick permission reference. Siri Shortcuts, Spotlight search, and Control Center integration.

⌨️

Mac-Native with Local File Scanning

Scan your local Mac folders and files directly. Full desktop support with keyboard shortcuts, drag-and-drop, context menus, and native folder picker. Works with your Mac's file system.

Built for the People Who Keep Systems Running

Whether you're preparing for a certification, managing production servers, or learning Unix for the first time

Sysadmins

Master the permissions that control every file, service, and process on your servers. Security audits, compliance reporting, and troubleshooting for Mac and Linux systems.

DevOps Engineers

Stop Googling chmod values. Know permissions cold so you can debug containers, fix deploys, and harden infrastructure without hesitation.

Students & Career Changers

Coming from Windows? The structured learning path takes you from zero to certification-ready. Certification exam prep coming in the next update.

Security Professionals

Scan for permission vulnerabilities based on OWASP, CIS Benchmarks, and NIST 800-53. Comprehensive checks for SSH keys, credentials, and sensitive configurations.

Mac Users & Developers

Manage permissions on your local Mac files and folders. Drag-and-drop folder scanning, keyboard shortcuts, and native sidebar navigation. Works natively with macOS.

One Purchase. Every Device.

Buy once, use everywhere. iCloud syncs your progress, streaks, and bookmarks across iPhone, iPad, and Mac.

📱 iPhone

iOS 17.0+

📱 iPad

iPadOS 17.0+

💻 Mac

macOS 14.0+

Simple, Fair Pricing

$3.99 $24.99
One-time purchase • No subscriptions • Every future update included
Currently still $3.99 — price increases to $24.99 with v3.2. Buy now and keep the introductory price forever.
One purchase. Lifetime access. No recurring fees.
Get Chmod Toolkit

Know someone studying for Linux+, LPIC, or RHCSA? Share this before the price increases.

What Users Are Saying

"Finally, a chmod tool that actually teaches you while you work. The security scanner caught issues I didn't even know to look for."

Sarah M.

DevOps Engineer

"The Mac Catalyst version is incredible. Drag-and-drop folder scanning saved me hours during our compliance audit."

James K.

System Administrator

"As a CS student, this app made Unix permissions finally click. The visual calculator and examples are brilliant."

Alex P.

Computer Science Student

Privacy First

Your file permissions and scan results never leave your device. No data collection, no tracking, no cloud storage. Everything happens locally.

🔒 On-Device Processing

All calculations, scanning, and OCR happen entirely on your device. No internet connection required.

🚫 No Data Collection

We don't collect, store, or transmit any of your data. No analytics, no tracking, no servers.

🌙 Dark Mode

Automatic dark mode support. Easy on your eyes during late-night server maintenance.

Join the community: r/chmodtoolkit

Tips, troubleshooting, and discussion on Unix file permissions.