About chmod Calculator

chmod Calculator converts a permission set between the three ways it is written: an octal number, the symbolic rwx string, and words.

It handles the special bits, setuid, setgid, and sticky, and it runs in your browser.

How to use it

  1. Enter permissions as octal or as a symbolic string.
  2. Read every other form, including the plain-English breakdown.
  3. Toggle the read, write, execute, and special bits to see the numbers change.

Common questions

What does 755 mean?

The owner can read, write, and execute; the group and everyone else can read and execute. It is the common setting for directories and scripts.

What is the leading fourth digit?

It holds the special bits: 4 is setuid, 2 is setgid, 1 is sticky. So 4755 is setuid plus 755.

Capital S or T in the symbolic string?

It means the special bit is set but the matching execute bit is not, which is usually a mistake worth checking.

Does anything leave my browser?

No. The tool runs entirely on this page.