chmod Calculator
Octal ↔ symbolic permissions
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chmod Calculator
Octal ↔ symbolic permissions
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About this tool
Toggle read/write/execute bits per user, group and other, and see the numeric and symbolic equivalents.
The chmod Permission Calculator is an indispensable utility for Linux, macOS, and Unix developers who need to convert between symbolic permission notation (rwxr-xr-x) and numeric octal notation (755) quickly and accurately. It eliminates the mental math and potential errors when setting file and directory permissions via the command line, preventing the common mistakes that lead to "permission denied" errors or dangerous over-permissioning.
Select individual permissions (read, write, execute) for owner, group, and others by clicking toggle buttons, and see both the symbolic string and octal number update in real time. The tool also provides the exact chmod command to apply, handles special modes like setuid, setgid, and sticky bit, and shows recommended permission values for common use cases like web server directories, SSH keys, and configuration files.
This is a pure calculator with no server interaction. Your file paths and server configuration details remain entirely on your machine — critical for security teams auditing permissions in sensitive environments.
Key features
Everything you get with chmod Calculator — no premium upsell.
Interactive permission grid with clickable read/write/execute toggles
Real-time symbolic (rwxr-xr-x) and octal (755) notation output
setuid, setgid, and sticky bit support with warnings for dangerous combinations
Ready-to-copy chmod command generated automatically
Recommended permissions for common scenarios (web roots, SSH keys, cron files)
Client-side only — no permission data transmitted anywhere
How to use chmod Calculator
Follow the steps below to use the tool.
- 1
Toggle Permissions
Click the read, write, and execute boxes for owner, group, and others to set the desired permissions.
- 2
View Octal and Symbolic
The numeric octal value (e.g., 755) and symbolic string (e.g., rwxr-xr-x) update instantly as you change selections.
- 3
Review Special Bits
Optionally enable setuid, setgid, or sticky bit, with contextual warnings about security implications.
- 4
Copy the Command
Click copy to get the ready-to-paste chmod command (e.g., chmod 755 script.sh) for your terminal.
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Launch chmod CalculatorFrequently asked questions
Quick answers before you launch the tool.
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