CHMOD Calculator
Click permission checkboxes and get the octal chmod value — or type an octal and see the permissions, live both ways.
This tool runs 100% in your browser. Your data is never uploaded, stored, or logged.
Permissions
Read (4)Write (2)Execute (1)
Owner
Group
Others
Result
About this tool
File permissions are a 9-checkbox grid pretending to be a number. This calculator syncs both representations live in both directions: tick read/write/execute for owner, group and others and watch the octal update, or type 755 and watch the boxes flip.
setuid, setgid and the sticky bit are supported, and common values get plain-language safety notes.
How to use it
- Tick the permissions you want — the octal value updates instantly.
- Or type an octal value (644, 755, 2775…) to set the boxes.
- Read the breakdown table and the safety note.
- Run the shown
chmodcommand on your server.
Useful ways to apply it
- Setting correct permissions on shared hosting (644 files, 755 folders).
- Understanding what a permission number in a tutorial actually grants.
- Configuring setgid on shared project directories.
- Avoiding 777 — the calculator warns you why.
Frequently asked questions
What do 4, 2 and 1 mean?
Read=4, write=2, execute=1. Each digit is the sum for one audience: owner, group, others. 754 = rwx (7) for owner, r-x (5) for group, r-- (4) for others.
What are safe permissions for websites?
Typically 644 for files and 755 for directories. PHP files don't need execute permission — the web server reads them.
What is the fourth digit (like 2775)?
Special bits: setuid=4, setgid=2, sticky=1. Setgid on a directory makes new files inherit the directory's group — handy for shared deploy folders.
Privacy
This tool runs 100% in your browser. Your data is never uploaded, stored, or logged.