chmod Calculator
Unix file permissions three ways — checkbox grid, octal (755, 4755) and symbolic (rwxr-xr-x) — all kept in sync whichever one you edit. With setuid, setgid and sticky bit, plus a plain-English explanation. Everything runs in your browser.
| Read (4) | Write (2) | Execute (1) | |
|---|---|---|---|
| Owner | |||
| Group | |||
| Others |
| Octal | Symbolic | Typical use |
|---|---|---|
| 644 | rw-r--r-- | Regular files: owner edits, everyone reads (web pages, configs) |
| 600 | rw------- | Private files: SSH private keys, .env, credentials — owner only |
| 755 | rwxr-xr-x | Executables & directories: everyone can run/enter, only owner writes |
| 700 | rwx------ | Private directories: ~/.ssh, personal scripts — owner only |
| 775 | rwxrwxr-x | Group-shared directories: team deploy folders, shared repos |
| 4755 | rwsr-xr-x | Setuid executable: runs as the file's owner (e.g. passwd) — use sparingly |
About this tool
Unix permissions are three octal digits — owner, group, others — where read=4, write=2, execute=1, summed per digit (rwx = 7, r-x = 5). An optional leading fourth digit holds the special bits: setuid=4 (executable runs as the file's owner), setgid=2 (runs as the file's group; on directories, new files inherit the group) and sticky=1 (on directories like /tmp, only a file's owner can delete it). In symbolic notation the special bits appear in the execute slots: s/t when execute is also set, S/T when it is not.
Remember: on a directory, "execute" means permission to enter it and access files inside — a directory without x is unusable even if it is readable. And chmod 777 is almost never the fix; it usually means the real problem is ownership (chown).
Everything is computed locally in your browser — nothing is sent anywhere.
Common chmod values explained
chmod 400 chmod 444 chmod 500 chmod 555 chmod 600 chmod 640 chmod 644 chmod 664 chmod 666 chmod 700 chmod 711 chmod 750 chmod 755 chmod 770 chmod 775 chmod 777 chmod 1777 chmod 2755 chmod 4755