chmod Calculator
Calculate Unix file permissions. Convert between numeric and symbolic chmod notation.
Quick Presets
Permissions
Result
Permission Breakdown
| Role | Read | Write | Execute | Symbolic | Octal |
|---|---|---|---|---|---|
| owner | Yes | Yes | Yes | rwx | 7 |
| group | Yes | No | Yes | r-x | 5 |
| others | Yes | No | Yes | r-x | 5 |
How to Use This Chmod Calculator
Calculate Unix file permissions interactively. Toggle checkboxes or type a numeric value to see the corresponding permissions.
- Use checkboxes to set read, write, and execute for Owner, Group, and Others
- Or type a 3-digit octal number (e.g., 755) in the numeric input
- View the numeric notation, symbolic notation, and chmod command
- Use quick presets for common permission values
FAQ
What does chmod 755 mean?
chmod 755 sets the file permissions so the owner can read, write, and execute (7), while the group and others can read and execute (5). This is the most common permission for directories and executable scripts.
What is the difference between numeric and symbolic notation?
Numeric notation uses three octal digits (e.g., 755), where each digit represents permissions for owner, group, and others. Symbolic notation uses letters r, w, x (e.g., rwxr-xr-x) to represent the same permissions in a human-readable way.
What does each number mean?
Read = 4, Write = 2, Execute = 1. Add the values to get the permission number for each role. For example, read + execute = 4 + 1 = 5.