Chmod Calculator
Visual permissions generator for Linux/Unix files. Convert between numeric (octal) and symbolic formats.
Linux Permissions (Octal)
e.g. 755Symbolic Notation
e.g. -rwxr-xr-xCommand
Chmod Calculator — Linux Permissions, Visualized
Tick read, write and execute boxes for owner, group and public, and this free chmod calculator instantly shows the octal number (like 755), the symbolic notation (like -rwxr-xr-x) and the ready-to-run chmod command.
Switch between file and directory targets, copy any output with one click, and browse common presets — from locked-down 600 for keys to the 755 web standard. Everything runs in your browser.
Octal, symbolic and command output
One set of checkboxes produces all three formats at once: the number, the -rwx string, and the exact chmod command to paste into your terminal.
One-click copy
Each output has its own copy button, so the octal value, symbolic notation or full command lands on your clipboard instantly.
Free developer utility
No signup, no uploads — permission math happens locally in your browser. Bookmark it for the next server setup.
How to use
- Tick the read, write and execute boxes for owner, group and public.
- Choose file or directory as the target type.
- Read the octal, symbolic and command outputs.
- Copy the format you need and paste it into your terminal.
Frequently Asked Questions
What do the chmod numbers mean?
Each digit sums permissions: read = 4, write = 2, execute = 1. So 6 means read+write (4+2), and 5 means read+execute (4+1).
What is the safest permission for web files?
755 for directories and 644 for files is the standard: only the owner can write, everyone else can only read.
What is the difference between chmod and chown?
chmod changes what people can do with a file (permissions); chown changes who owns the file (ownership).
How do I change permissions recursively?
Add the -R flag, e.g. chmod -R 755 /path/to/directory — but use it carefully, since it affects every file inside.
Why do I get 'Operation not permitted'?
You can only chmod files you own. For files owned by someone else, prefix the command with sudo to run it as root.
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