Chmod Calculator

What is Chmod Calculator?

Chmod Calculator is a free online tool for converting Unix file permissions between octal notation (like 755 or 4755) and symbolic notation (like rwxr-xr-x or rwsr-xr-x). Permissions control who can read, write or execute a file — and getting them wrong means broken deployments or wide-open secrets. Toggle the checkboxes, type an octal value, or paste an ls -l string; every representation updates instantly, including the setuid, setgid and sticky bits that most calculators quietly drop.

Features

• Bidirectional conversion — edit the octal value, the symbolic string, or the checkbox matrix; all three stay in sync
• Full special-bit support — setuid (s/S), setgid (s/S) and sticky (t/T) encode and decode correctly in both directions, so 4755 really does round-trip to rwsr-xr-x
• ls -l paste friendly — a 10-character string like -rw-r--r-- is accepted directly; the leading file-type character is stripped for you
• Common presets — one-click chips for 755, 644, 777, 700, 600 and 400
• Clear errors — invalid octal digits, wrong lengths and unsupported X notation are called out with the exact position that failed

How to use

Tick the read/write/execute boxes for Owner, Group and Others, plus any special bits, and read the octal and symbolic values off the right card. Or work the other way: type 755 into the octal field (or paste rwxr-xr-x into the symbolic field) and the checkboxes follow. Click a preset chip for the permissions everyone actually uses, then copy the result.

Privacy

Conversion runs locally in the browser UI. Permission strings you enter on the page are not uploaded or logged.