Chmod Calculator
Visually compute Unix file permissions (octal + symbolic).
chmod 644 filename
About the Chmod Calculator
Compute Unix file permissions by clicking Read, Write and Execute checkboxes for Owner, Group and Public. The octal digits, the rwx symbolic string and a ready-to-run chmod command update as you toggle, and well-known values like 755 or 644 come with a short explanation of what they mean in practice.
How to use the Chmod Calculator
- Tick Read, Write and Execute for each of the three groups: Owner, Group and Public.
- Watch the octal value and rwxrwxrwx string update together.
- Copy the chmod command from the output box.
- Check the note beneath for guidance when you land on a common value like 644 or 777.
Chmod Calculator FAQ
How are the octal digits computed?
Each group sums its enabled bits โ read is 4, write is 2, execute is 1 โ so read plus write gives 6, and the three groups produce digits like 755.
What does the tool say about 777?
It warns that anyone can do anything and to avoid that mode on production servers, while values like 600 for SSH keys get a note about owner-only access.
Can I convert an existing octal value?
Work backwards from the digits: enable Read for a group to add 4, Write for 2 and Execute for 1 until the displayed octal matches what ls or stat reported.