DevToolKit

Chmod Calculator

Calculate Unix/Linux file permissions. Toggle checkboxes to build your chmod value instantly.

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Permission Selector
Read (r)
Write (w)
Execute (x)
Owner (u)
Group (g)
Others (o)
Result
Numeric644
Symbolicrw-r--r--
Commandchmod 644 filename
Enter Octal Directly
Common Presets

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What is Chmod?

chmod (change mode) is a Unix/Linux command used to set file and directory permissions. Permissions control who can read, write, or execute a file — for the owner, the group, and all other users.

Numeric vs. Symbolic Notation

Permissions can be expressed as a 3-digit octal number (like 755) or as a symbolic string (like rwxr-xr-x). Each digit represents one class of user: owner, group, others. Each bit within a digit represents read (4), write (2), and execute (1) permissions.