Chmod Calculator

Convert between numeric and symbolic chmod permissions and copy a ready command.

Numeric input

Enter three digits from 0 to 7. A leading-zero form like 0755 is accepted and normalized to 755. Special bits such as 4755 are not supported in this version.

Permission toggles

Read Write Execute
User
Group
Other

Permission outputs

Normalized octal mode

644

Symbolic permissions

rw-r--r--

Ready-to-copy command

chmod 644 file

When to use Chmod Calculator

Common ways to use Chmod Calculator:

  • Set web server file permissions

    Quickly build the octal value to make web files readable by the server but not writable by others.

  • Make a script executable

    Find the right chmod value to add execute permission without opening up unneeded write access.

  • Restrict sensitive directory access

    Lock down keys, configs, or private directories to owner-only with the correct numeric mode.

  • Review symbolic and octal notation together

    Check how rwxr-xr-x maps to 755 by toggling read, write, and execute permissions and comparing the live outputs.

  • Verify permissions before deploying

    Double-check that your chmod commands give the correct permissions before pushing to production.

Chmod Calculator FAQ

How do I use Chmod Calculator?
Enter an octal mode such as 755 or 0755, or toggle the read, write, and execute checkboxes for user, group, and other. The octal mode, symbolic permissions, and ready-to-copy chmod command update instantly.
Is this tool free to use?
Yes. Chmod Calculator is free to use, works in your browser, and does not require an account.
What happens to the permission data I enter?
The calculator itself runs locally in your browser and does not upload or store the permission values you enter. Standard site analytics may still load on production pages.
Why am I seeing an invalid octal error?
Use only digits 0 through 7 and enter exactly three permission digits, such as 644, 755, or 0755. The tool accepts a leading zero and normalizes it automatically, but special bits such as 4755 are not supported in this version.
Where can I find help and troubleshooting tips?
Open the in-app Help panel for step-by-step instructions and quick tips. The panel is keyboard accessible, and you can close it with Escape.