Chmod Calculator
Toggle rwx for owner, group, and others to get the octal and symbolic chmod.
Build chmod permissions visually
Unix file permissions are simple once you see them, but translating between the rwx letters and the octal numbers chmod wants is easy to fumble. Tick the boxes for owner, group, and others and this shows both the octal and symbolic forms.
Owner rwx, group r-x, others r-x gives 755 and the string rwxr-xr-x — a standard setting for a script or directory. Every toggle updates both outputs instantly, so you can dial in exactly the mode you need.
Clear and private
The mapping is done with plain bit math in your browser, so there is nothing to install and nothing is uploaded.
Frequently Asked Questions
How do the octal numbers work?
Each of read (4), write (2), and execute (1) adds to a digit per class, so rwx = 7, rw- = 6, r-x = 5. Three digits cover owner, group, and others.
What is the symbolic form?
The nine-character string like rwxr-xr-x that ls shows — the same permissions written as letters instead of numbers.
What is a safe default?
755 for directories and executables (owner full, others read/execute) and 644 for regular files are common, sensible defaults.
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