Chmod permissions calculator
Tick boxes or type a number like 755 to see Unix file permissions both ways — octal and rwx notation — plus the exact command to run.
| Read (4) | Write (2) | Execute (1) | |
|---|---|---|---|
| Owner | |||
| Group | |||
| Others |
Runs entirely in your browser. Nothing you enter is sent to a server.
Reading permissions
Each digit is the sum of read (4), write (2) and execute (1) for the owner, the group and everyone else. So 7 = 4+2+1 = rwx, 5 = 4+1 = r-x and 4 = r--. That makes 755 “owner can do everything; others can read and run”, and 644 “owner can read and write; others can only read”.
For folders, execute means “can enter the folder”, which is why directories usually need 755 or 700, not 644.
Recommended defaults
- Web files: 644. Web folders: 755.
- SSH private keys (
~/.ssh/id_ed25519): 600, or SSH refuses to use them. ~/.sshfolder: 700.
Scheduling a script you just made executable? Check its timing with the cron explainer.
Frequently asked questions
What does chmod 755 mean?
Owner: read, write and execute. Group and others: read and execute. Symbolically, rwxr-xr-x.
What does chmod 644 mean?
Owner: read and write. Group and others: read only. Symbolically, rw-r--r--.
Why is 777 dangerous?
It lets every user on the system change or replace the file, which attackers can use to inject code.