Chmod Calculator — 755 and Symbolic Permissions
DeveloperA chmod calculator is a developer tool that converts Linux/Unix file permissions between rwx checkboxes, octal notation (e.g. 755), and symbolic notation (e.g. rwxr-xr-x).
What is it
Linux file permissions combine read (r=4), write (w=2), and execute (x=1) for three audiences: owner, group, and others. Concatenating the three sums gives octal notation like 755, and the same permissions appear as rwxr-xr-x in ls -l output. In this tool, changing any representation — checkboxes, octal, or symbolic — updates the others instantly, along with a ready-to-copy chmod command. Special bits (setuid, setgid, sticky) are out of scope, and everything is computed in your browser.
How to use
- 1Toggle r/w/x for owner, group, and others.
- 2Or type the octal value (755) or symbolic string (rwxr-xr-x) directly.
- 3Copy the synchronized notation or the example chmod command.
Reference
| Octal | Symbolic | Typical use |
|---|---|---|
| 644 | -rw-r--r-- | Default for regular files |
| 755 | -rwxr-xr-x | Executables and directories |
| 600 | -rw------- | Private keys, .env secrets |
| 700 | -rwx------ | Owner-only directories |
| 664 | -rw-rw-r-- | Group-writable files |
| 777 | -rwxrwxrwx | Everything allowed — avoid |
Sources & standards
- POSIX chmod utility - The Open Group
- MDN Web Docs: Client-side web APIs - MDN Web Docs
FAQ
What does chmod 755 mean?
The owner can read, write, and execute (7=4+2+1); the group and others can read and execute (5=4+1). It is the most common mode for executables and directories.
Why should I avoid 777?
Because every user can modify and execute the file, which makes it easy for attackers to plant malicious code. Web content is usually fine with 644 for files and 755 for directories.
Are setuid and sticky bits included?
No. This tool covers the basic nine bits (rwx × 3). The leading digit of a four-digit octal mode (setuid=4, setgid=2, sticky=1) must be set separately.
Does this tool talk to a server?
No. All conversion happens in your browser and nothing is transmitted.