chmod Permission Calculator
Convert between octal (755) and rwx file permissions.
| Read (r/4) | Write (w/2) | Execute (x/1) | |
|---|---|---|---|
| Owner | |||
| Group | |||
| Other |
All calculations run entirely in your browser — never uploaded or stored.
What is this tool?
The chmod permission calculator converts Linux/Unix file permissions between checkboxes and octal notation instantly. Toggle a checkbox and the octal value, symbolic notation (rwxr-xr-x), and chmod command update live — or type an octal value and the checkboxes update to match.
Octal and rwx notation
- 3-digit octal: owner, group, other in order; each digit is the sum of read(4) + write(2) + execute(1).
- Symbolic notation: shows owner/group/other permissions as letters, e.g. rwxr-xr-x.
- Special bits: enabling setuid(4000)/setgid(2000)/sticky bit(1000) adds a 4th octal digit and changes the execute slot to s/S or t/T in the symbolic notation.
Note: To apply it on a real server, run the displayed chmod command in your terminal.
Privacy & processing
Everything runs in your browser. Inputs and results are never uploaded or stored, and you can copy the command to your clipboard.
FAQ
What does a chmod number like 755 mean?
chmod permissions are expressed as a 3-digit octal number for owner, group, and other. Each digit is the sum of read(4), write(2), and execute(1). For example, 755 grants the owner read/write/execute(7) and grants group/other read/execute only(5).
What do r/w/x each mean?
r (read) lets you view a file's contents or list a directory, w (write) lets you modify a file or create/delete files in a directory, and x (execute) lets you run a file or enter a directory. The symbolic form rwxr-xr-x lists owner, group, and other permissions in three-character groups.
When are setuid, setgid, and sticky bit used?
setuid(4000) makes a program run with the file owner's privileges, setgid(2000) makes it run with the group's privileges or makes new files in a directory inherit the parent group, and sticky bit(1000) restricts shared directories (e.g. /tmp) so only the owner can delete their own files. These are represented as the leading digit of a 4-digit octal value.
How do I apply the calculated permission on a real server?
Type the displayed command (e.g. chmod 755 filename) into your terminal. You can also apply it using symbolic notation, such as chmod u=rwx,g=rx,o=rx filename.
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