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chmod Calculator
COMMON MODES
// about this tool

chmod Calculator Online

Updated 2026-08-04

// how to use

  1. 1 Type either form — 755 or rwxr-xr-x. The tool works out which you meant.
  2. 2 Click any cell in the grid to toggle that permission and watch both forms update.
  3. 3 Copy the ready-made chmod command, or pick a row from the common modes below.

// examples

Octal to symbolic
Input
755
Output
rwxr-xr-x — owner does everything, group and others read and execute
Symbolic to octal
Input
rw-r--r--
Output
644, the normal mode for a file
A sticky directory
Input
1777
Output
rwxrwxrwt — anyone can write, but only the owner can delete their own files

// common uses

Working out what a mode you found in a script actually permits Getting the right number for a deploy step or Dockerfile Checking whether a file is world-writable before shipping Explaining setuid and the sticky bit to someone

// faq

What do the numbers actually mean?
Each digit is read (4) plus write (2) plus execute (1), added together, once for the owner, once for the group and once for everyone else. So 7 is 4+2+1 (everything), 6 is 4+2 (read and write), 5 is 4+1 (read and execute). That is the whole system.
What is the fourth digit some modes have?
The special bits — setuid (4), setgid (2) and sticky (1). 4755 means setuid plus 755. They change who a program runs as, or who may delete files in a directory, and they are worth a second look whenever you see one you did not add deliberately.
Why does the symbolic form sometimes show s or t instead of x?
Because those positions carry two pieces of information at once. Lowercase s or t means the special bit is set AND execute is set; uppercase S or T means the special bit is set but execute is not. Reading them as a plain execute bit is how the setuid bit gets lost in translation.
Should I ever use 777?
Almost never on a server. It lets every account on the machine modify the file, which is both a security problem and a common cause of "it works on my machine". If something only runs at 777, the real fix is usually ownership, not permissions.
Does this work on a paste from ls -l?
Yes. A leading file-type character like the - or d in -rw-r--r-- is ignored, so you can paste a line straight out of ls.

// works with your data

IPv4 Subnet Calculator Number Base Converter Octal to Decimal Decimal to Octal Hash Generator

Use this via API

Get a free API key → 
curl -X POST https://thesnaptools.com/api/v1/tools/chmod-calculator \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"mode":"755"}'
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