Chmod Calculator

How to use

1. 1Pick whether the target is a file or a directory so the plain-English description and umask use the right defaults.
2. 2Type an octal value (for example 755 or 1777) into the Octal field, type a symbolic value (for example rwxr-xr-x) into the Symbolic field, or tick the checkboxes for owner, group, and other; the other views update automatically.
3. 3Toggle setuid, setgid, or the sticky bit when you need a fourth digit; the value will render with a leading 0 (for example 1777 or 2755).
4. 4Use the preset chips (644, 755, 700, 1777, 2755, and more) to load common combinations with one click.
5. 5Copy the chmod command in octal form, the symbolic chmod form, the equivalent umask, or any individual value with the Copy buttons.

About this tool

Chmod Calculator turns the read, write, and execute permissions on a Unix or Linux file or directory into the exact chmod value you need. Three views stay perfectly in sync against one canonical 12-bit permission state. Type an octal value (3 digits like 755 or 4 digits like 1777) and the symbolic and checkbox views update instantly. Type a symbolic string (9 characters like rwxr-xr-x, or 10 with a leading file-type character from ls -l output) and the octal and checkbox views update. Tick the checkboxes for owner, group, and other (the three permission classes Linux uses) and both string forms update. The special-permission row covers setuid (so an executable runs as its owner), setgid (so an executable runs as its group, or, on a directory, so new files inherit the group), and the sticky bit (so on directories like /tmp only the owner of a file can delete it). Choose whether the target is a file or a directory and the plain-English description on the right rewrites itself accordingly: read on a file means view, on a directory means list contents; execute on a file means run as a program, on a directory means enter the directory. The output panel shows the canonical octal value (with a leading zero for the special bits when they are set), the full ls -l style symbolic string, a per-class breakdown with the digit value (so 7 = 4 + 2 + 1 = read + write + execute), copy-ready chmod commands in both octal (chmod 755 path) and POSIX symbolic (chmod u=rwx,g=rx,o=rx path) form, and the equivalent umask that would produce these permissions from the standard 0666 default for files or 0777 default for directories. Common presets cover 644, 664, 666, 600, 700, 711, 750, 755, 775, 777, 1777 (sticky-bit /tmp), and 2755 (setgid binary or shared directory). Useful for sysadmins setting up a server, developers writing a Dockerfile RUN chmod line, anyone reading the output of ls -l on a strange permission set, students learning how Unix permissions work, and anyone deciding what number to type after chmod when 644 versus 755 versus 600 is the difference between something working and not working. The whole calculator runs locally in your browser, so the paths and permission sets you type here never leave your device.

Free to use. Works in your browser. No signup, no login.