Enter a chmod octal value (like 755 or 644) or click the permission checkboxes to build a permission set. The tool shows both the numeric value and the symbolic rwx notation.
| Read | Write | Execute | Value | |
|---|---|---|---|---|
| Owner | 7 (rwx) | |||
| Group | 5 (r-x) | |||
| Other | 5 (r-x) |
The tool converts between octal, symbolic, and binary permission representations using pure JavaScript bit arithmetic. No library required. Checking a box sets the corresponding bit; typing an octal value like 755 reverses the process to tick the right boxes.
All calculations happen locally in the page. Our servers are not involved at any point.
For subnet math like host counts and netmasks, try the CIDR calculator. To convert numeric permission bits between bases, use the number base converter. For testing permission patterns in path strings, see the regex tester.
Run chmod followed by the permission value and filename. For example: chmod 755 script.sh makes a script executable by everyone. chmod 644 file.txt gives the owner write access and everyone else read-only.
Each permission group (owner, group, other) is a sum of its bits: read=4, write=2, execute=1. So rwx=7, rw-=6, r-x=5, r--=4, ---=0. A permission of 755 means owner=7 (rwx), group=5 (r-x), other=5 (r-x).
Yes. chmod u+x file.sh adds execute for the owner. chmod go-w file removes write from group and others. chmod a+r file adds read for all. Symbolic notation is useful for adding or removing specific permissions without resetting others.