Chmod Calculator
Calculate Unix file permissions with a visual chmod calculator. Toggle read, write, execute bits for owner, group, and others. Get octal, symbolic notation, and ready-to-use commands.
Enter a 3-digit octal number (e.g., 755)
| Read(4) | Write(2) | Execute(1) | Value | |
|---|---|---|---|---|
| Owner | 7 | |||
| Group | 5 | |||
| Other | 5 |
755
-rwxr-xr-x
chmod 755 filename
All calculations happen in your browser. No data is sent to any server.
How to Use This Tool
- 1
Toggle permission bits
Click the permission buttons to toggle read (r), write (w), and execute (x) for owner, group, and other.
- 2
Enter octal value
Type a 3-digit octal number (like 755) in the input field. The permission matrix updates automatically.
- 3
Use presets
Click common presets like 644 (files) or 755 (directories) to quickly set standard permissions.
- 4
Copy the result
Copy the octal value, symbolic notation (rwxr-xr-x), or the full chmod command to your clipboard.
Frequently Asked Questions
- What is chmod?
- chmod (change mode) is a Unix/Linux command used to change file and directory permissions. It controls who can read, write, or execute a file.
- What do the numbers 4, 2, 1 mean?
- In octal notation, 4 = read (r), 2 = write (w), 1 = execute (x). Add them together for combined permissions: 7 = rwx, 6 = rw-, 5 = r-x, etc.
- What is the difference between 644 and 755?
- 644 (rw-r--r--) is typical for files: owner can read/write, others can only read. 755 (rwxr-xr-x) is typical for directories: owner has full access, others can read and enter.
- Is my data secure?
- Yes. All permission calculations happen entirely in your browser using JavaScript. No data is sent to any server.