Chmod Calculator
Toggle rwx checkboxes for owner, group and others to get octal and symbolic permissions.
| Who | Read (4) | Write (2) | Execute (1) | Digit |
|---|---|---|---|---|
| Owner (u) | 7 | |||
| Group (g) | 5 | |||
| Others (o) | 5 |
Owner: read, write, execute · Group: read, execute · Others: read, execute
Frequently Asked Questions
How does the octal number work?
Each group (owner, group, others) gets a digit: read = 4, write = 2, execute = 1. Add the values for the permissions granted — read+write+execute is 7, read+execute is 5, read-only is 4.
What does chmod 755 mean?
The owner can read, write and execute (7), while group and others can read and execute (5). It is the standard permission for scripts and web directories.
Why is 777 considered risky?
777 gives everyone full read, write and execute access. On a shared server any user could modify or replace the file, so avoid it unless a specific app truly requires it.
What is the symbolic form?
Commands like chmod u+rwx,g+rx,o-rwx use u (user/owner), g (group), o (others) and a (all) with + to add and - to remove permissions. The tool shows both notations.
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