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chmod Calculator

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Convert between octal, symbolic, and descriptive Unix file permissions

Toggle read/write/execute checkboxes for owner, group, and others and get back both the octal number and the symbolic string (like `rwxr-xr-x`) you'd see from `ls -l`, or go the other way and paste either format to decode it into plain permissions before running `chmod` against a production server. Setuid, setgid, and the sticky bit are all supported as the special fourth octal digit or their symbolic `s`/`S`/`t`/`T` equivalents, and a reference table covers common permission sets like 755, 644, and 600 so you don't have to reconstruct them from scratch each time. This is a pure calculator: it never touches a filesystem or actually runs `chmod` for you, so applying the permissions is still a manual step in your own terminal.

chmodpermissionsunixlinuxoctal

How to use chmod Calculator

  • 1.Toggle read/write/execute checkboxes for owner, group, and others to get the corresponding octal (e.g. `755`) and symbolic (`rwxr-xr-x`) permission strings.
  • 2.Paste an octal number like `644` to see exactly what permissions it grants before running a `chmod` command on a production server.
  • 3.Use it to decode a symbolic permission string you see in `ls -l` output when you're not sure what access level it actually represents.

Frequently asked questions

Does this cover special permission bits like setuid, setgid, or sticky bit?
Basic read/write/execute for owner/group/others is the core focus — check for a 4th leading digit or special bit toggle if your use case needs setuid/setgid/sticky, since not all chmod calculators expose these.
Does it actually change file permissions on my system?
No, this is a calculator only — it translates between notations but doesn't run `chmod` or touch any files; you still need to run the command yourself in a terminal.
What's the difference between octal and symbolic notation?
Octal (`755`) represents each permission set as a single digit (sum of read=4, write=2, execute=1), while symbolic (`rwxr-xr-x`) spells out each permission letter per role — both describe the same permissions, just formatted differently.
Is my input sent anywhere?
No, all conversion happens locally in your browser.

Availability

This tool currently runs in the browser only — no REST API, SDK, or MCP equivalent yet.

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