chmod Calculator (Unix/Linux Permissions)
Check the read, write and execute permissions for owner, group and others, and get the numeric value (chmod 755), the symbolic form (rwxr-xr-x), and a ready-to-copy command.
How the number is calculated
Each permission is worth a number: read = 4, write = 2, execute = 1. The active ones are added up for each group (owner, group, others), giving a digit from 0 to 7 for each — for example, read + write + execute = 4+2+1 = 7.
| Permissions | Value |
|---|---|
| None | 0 |
| Execute | 1 |
| Write | 2 |
| Write + execute | 3 |
| Read | 4 |
| Read + execute | 5 |
| Read + write | 6 |
| Read + write + execute | 7 |
chmod 755, the most common pattern
755 is a very common pattern: the owner can read, write and execute (7); the group and everyone else can only read and execute (5), but not modify the file. For a web page or an executable script that shouldn't be edited by other users on the server, it's a typical choice.