ABC Tools
Chmod Calculator illustration

Chmod Calculator

Converts Unix file permissions between octal (755), symbolic (rwxr-xr-x) and checkbox form — including setuid, setgid and the sticky bit — and explains what each combination actually allows. Paste a whole "ls -l" line and the matrix fills itself; get both copy-ready commands (chmod 755 and chmod u=rwx,g=rx,o=rx); switch between file and directory to see what read, write and execute really mean for each. One-click presets (644, 755, 600, 700, 1777) explain when to use them, and world-writable or 777 modes get a clear warning.

Runs 100% in your browser — nothing you paste leaves your device.

Read the full guide to this tool

Notes

  • Directories need execute (x) to be entered: a directory with r-- can be listed but not descended into.
  • The sticky bit on a directory (chmod +t, shown as t) means only a file's owner can delete it — that is how /tmp works.
  • A lowercase s or t in ls output means the special bit plus execute; a capital S or T means the special bit WITHOUT execute — almost always a misconfiguration.
  • Runs 100% in your browser — nothing you paste leaves your device.

Explore the idea

This interactive demo needs JavaScript.

Read the full guide for the explanation behind it

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