Chmod Visual Calculator
Fast, accurate and free online chmod visual calculator tool running directly in your browser.
-
1Enter data
Enter content, paste text or load a file from disk. -
2Click the button
The tool will immediately process your data in the browser. -
3Get the result
Copy the finished text or save the file to your device.
return "Result ready in 0.1s";
}
Rate this tool:
Related tools
Other tools you may find usefulChmod Calculator – Unix/Linux File Permissions Without Guessing
chmod (change mode) is a Unix command for setting file or directory permissions. Permissions consist of three classes (owner, group, others) and three types (read, write, execute). The calculator converts between octal (755) and symbolic notation (rwxr-xr-x).
Unix permission system
Each file has 3 classes × 3 types = 9 permission bits + 3 special bits (setuid, setgid, sticky). Classes: u (user/owner), g (group), o (others), a (all). Types: r (read=4), w (write=2), x (execute=1). Octal notation: each class = sum r+w+x. 7=rwx, 5=r-x, 4=r--.
Popular chmod combinations
644 (rw-r--r--): static files (HTML, CSS, images). The owner can read and write, the rest only reads. 755 (rwxr-xr-x): directories and executable scripts. The owner has full rights, the rest reads and executes. 600 (rw-------): sensitive files (SSH private key, .env). Only the owner has access. 777 (rwxrwxrwx): everyone has full rights - DANGEROUS.
Special bits
Setuid (4000): executable runs with owner rights (e.g. /usr/bin/passwd). Setgid (2000): on file – runs as a group; on the directory – new files inherit the group. Sticky bit (1000): on a directory (e.g. /tmp) – users can only delete their own files. Notation: chmod 1755 dir = sticky + rwxr-xr-x.
Symbolic notation
chmod [ugoa][+-=][rwxXst] file. Examples: chmod u+x file (add execute for owner). chmod go-w file (remove write for group and others). chmod a=r file (set everything to read only). chmod +x script.sh (add execute to all). chmod u=rwx,go=rx dir = chmod 755 dir.
FAQ
What permissions should I set for the webroot directory?
Secure settings for the web server (Apache/nginx, user=www-data): directories = 755, PHP/HTML/CSS/JS files = 644, .env and config files with passwords = 600. Owner: your account (admin). Never 777 - risk of malicious code execution by www-data.
Why is chmod 777 dangerous?
777 = all system users can read, write and execute. On a shared hosting server: any other account can overwrite your files. Possibility to upload web shell. Apache/nginx run as www-data – with 777 it can also write, which is an attack vector. Use 755 for directories and 644 for files.
How to check file permissions?
ls -la: list with permissions (drwxr-xr-x). stat file.txt: detailed description. find . -perm 777: find files from 777. find . -perm /u+s: find setuid. stat -c "%a %n" *: octal permissions for all files. Online tool: paste symbolic permissions and converts to octal.
What does the "d" at the beginning of permissions mean?
ls -la: drwxr-xr-x – "d" = directory. - = regular file. l = symbolic link. c = chardevice. b = block device. p = named pipe (FIFO). s = socket. chmod does not change this first character.
How to set permissions recursively?
chmod -R 755 directory: change all files and directories recursively. Problem: files should be 644, not 755. Elegant solution: find directory -type d -exec chmod 755 {} \; && find directory -type f -exec chmod 644 {} \;. Setuid/setgid: -R may be dangerous - check what you are modifying.
Related tools: JSON validator, test data generator and development tools.