Chmod Calculator
Interactive Unix file permission calculator. Toggle permissions with checkboxes or enter a numeric value. Get the chmod command ready to copy and paste.
Permission Grid
| Class | Read (4) | Write (2) | Execute (1) | Octal | Symbolic |
|---|---|---|---|---|---|
| Owner (u) | 7 | rwx | |||
| Group (g) | 5 | r-x | |||
| Other (o) | 5 | r-x |
Chmod Command
chmod 755 filenamechmod u=rwx,g=rx,o=rx filenameCommon Presets
Quick Reference
Octal Values
Permission Classes
Frequently Asked Questions
What does chmod 755 mean?
chmod 755 sets the owner to read, write, and execute (7), group to read and execute (5), and others to read and execute (5). In symbolic notation this is rwxr-xr-x. It is the standard permission for directories and executable scripts on Linux and macOS.
What does chmod 644 mean?
chmod 644 sets the owner to read and write (6), group to read-only (4), and others to read-only (4). In symbolic notation this is rw-r--r--. It is the standard permission for regular files like HTML pages, CSS stylesheets, and configuration files.
What is the difference between numeric and symbolic chmod?
Numeric (octal) mode uses three digits (e.g., 755) where each digit represents owner, group, and other permissions. Each digit is the sum of read (4), write (2), and execute (1). Symbolic mode uses letters: r (read), w (write), x (execute) combined with u (user/owner), g (group), o (other) to set permissions more granularly.
Is this chmod calculator safe to use?
Yes. This tool runs entirely in your browser. No data is sent to any server. It simply calculates permission values and generates commands — it does not modify any files on your system.
What are common chmod permission values?
The most common values are: 755 for directories and executables, 644 for regular files, 600 for private files like SSH keys, 700 for private directories, 777 for full access (generally insecure), and 664 for group-writable files.