UsefulTab
Chmod Calculator
Permissions to octal and symbolic.
-rw-r--r--
chmod 644 file
Calculate chmod permissions
Tick read, write, and execute for the owner, group, and everyone else, and the calculator shows the matching octal mode (like 755), the symbolic string (like -rwxr-xr-x), and the ready-to-run chmod command. Type an octal value instead and the checkboxes update to match, so it works both ways. Useful for setting script, directory, and SSH key permissions correctly. Everything is computed in your browser — nothing is sent anywhere.
Common questions
What do the three permission bits mean?
Read (r = 4) lets you view a file or list a directory, write (w = 2) lets you change it, and execute (x = 1) lets you run a file or enter a directory. Each class — owner, group, others — gets its own combination, added together into one octal digit (so rwx = 4+2+1 = 7).
What is the difference between octal and symbolic?
Octal is the three-digit numeric form chmod accepts, like 644. Symbolic is the human-readable string ls -l shows, like -rw-r--r--, where the first character is the file type and the next nine are owner/group/other permissions. Both describe the same thing.
What permissions should I use?
Common choices: 644 for regular files (owner can edit, others read), 755 for scripts and directories (everyone can run/enter, only owner edits), 600 for private files like SSH keys, and 700 for private directories. Avoid 777 — it lets anyone write, which is a security risk.
Does this change any files?
No. It only calculates the mode and prints the chmod command for you to copy and run yourself. Nothing on your system is touched by this tool.
Is anything uploaded?
No. The calculation is pure arithmetic done in your browser. Nothing you enter is sent to a server.