chmod Calculator — Octal & Symbolic Permissions

Type a permission as octal (755) or symbolic (rwxr-xr-x), or tick the boxes. The octal, symbolic, chmod command and a plain-English explanation update live — entirely in your browser.

ReadWriteExecute
Owner
Group
Others

Result

Octal
Symbolic
Command

In plain English

How Unix file permissions work

Every file has three permission classes — owner, group, and others — and each class can be granted read (4), write (2), and execute (1). Add the numbers within a class to get its octal digit: rwx = 4+2+1 = 7, r-x = 4+1 = 5, r-- = 4. Three digits make a full mode like 755.

Looking for a specific one? Browse common permissions on the home page.