Calculate umask

Calculate the file and directory modes produced by a Unix umask.

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ToolUmask Calculator
Input
Output
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Preview

How it works

Regular files start from 0666 and directories from 0777; the umask removes permission bits from those baselines. Octal and symbolic forms are converted to the resulting mode while special bits stay separate.

  • The file-versus-directory baselines explain different execute results.
  • The defaults mirror POSIX process creation rules.

Worked example

The common 022 umask
Group and others lose write permission
Input
											022
Output
												File permissions octal: 644
File permissions symbolic: rw-r--r--
Directory permissions octal: 755
Directory permissions symbolic: rwxr-xr-x

When to use this

Shell profiles, Linux services, and container entrypoints calculate inherited permissions.

Edge cases

  • 022 yields 0644 files but 0755 directories.
  • Symbolic masks are interpreted by owner, group, and other classes.
  • Setuid, setgid, and sticky bits require separate mode handling.

References