Chmod Calculator
Convert Unix and Linux file permissions between octal (755) and symbolic (rwxr-xr-x) form.
About the Chmod Calculator
Each of owner, group and others gets read (4), write (2) and execute (1) permission; add them for each digit, so 7 = rwx, 5 = r-x and 4 = r--. 755 is typical for programs and folders; 644 for ordinary files; 600 for private keys. A fourth leading digit sets setuid (4), setgid (2) and the sticky bit (1).
The formula
Digit = 4 × read + 2 × write + 1 × execute
Common permissions
| Octal | Symbolic | Use |
|---|---|---|
| 755 | rwxr-xr-x | Programs, folders |
| 644 | rw-r--r-- | Normal files |
| 600 | rw------- | Private keys, secrets |
| 700 | rwx------ | Private folders |
| 777 | rwxrwxrwx | Avoid: anyone can modify |
Worked example
Example: chmod = 644 (rw-r--r--)
- Input: Permissions (octal like 755 or symbolic like rwxr-xr-x): 644.
- Formula: Digit = 4 × read + 2 × write + 1 × execute
- Result: chmod = 644 (rw-r--r--)
Questions people ask
What does chmod 777 do?
Gives everyone full access; it's a security risk.
Why does a folder need x?
Execute on a folder lets you enter it and reach files inside.