Chmod Calculator
Convert Unix file permissions between octal and rwx symbolic notation.
Tick the read, write and execute boxes for owner, group and others to get the matching chmod octal number (like 755), the symbolic string (rwxr-xr-x) and a ready-to-copy chmod command. Type an octal value to work the other way. Includes setuid, setgid and sticky bits. Runs entirely in your browser.
| Permission | Owner | Group | Others |
|---|---|---|---|
| Read | |||
| Write | |||
| Execute |
755rwxr-xr-xchmod 755 fileFormula & methodology
Each permission class (owner, group, others) is a 3-bit value where read=4, write=2, execute=1. The optional leading digit encodes setuid=4, setgid=2 and sticky=1.
Worked example
- 755 → rwxr-xr-x · chmod 755 file
- rw-r--r-- → 644
Frequently asked questions
What does chmod 755 mean?
The owner can read, write and execute (7), while group and others can read and execute but not write (5). It is common for scripts and directories.
What is the fourth (leading) digit?
It sets special bits: 4 = setuid, 2 = setgid, 1 = sticky. For example 4755 sets the setuid bit on an otherwise 755 file.
Privacy
All processing happens locally in your browser. Your data is never uploaded.