chmod कैलकुलेटर.

Standard Unix permission bits only; ACLs and SELinux labels are not covered. Everything is calculated in your browser; nothing you type is uploaded.

Each class (owner, group, others) adds read = 4, write = 2 and execute = 1. A fourth leading digit sets setuid (4), setgid (2) and the sticky bit (1), shown as s, s and t in the symbolic form.

755 is rwxr-xr-x: the owner can read, write and run the file; group and others can read and run it. 1777 adds the sticky bit (rwxrwxrwt).