Chmod Calculator

Click the read/write/execute boxes for owner, group and others to get the octal mode — or type a number like 755 and watch the boxes light up. The symbolic form (rwxr-xr-x) and the exact chmod command come with it.

Runs locally — nothing you enter is sent Developer Free · no signup

How to use

Tick the permissions each class (owner, group, others) should have — the octal updates live.
Or type an octal mode (755, 644, 600…) to set the boxes.
Copy the generated chmod command.

Examples

755

rwxr-xr-x — scripts & directories

644

rw-r--r-- — typical files

600

rw------- — private keys

Supported formats

Three-digit octal modes (0–7 per digit: read=4, write=2, execute=1).

Privacy

This tool runs entirely in your browser. Nothing you enter or open is sent anywhere. Privacy policy.

Limitations

Special bits (setuid 4xxx, setgid 2xxx, sticky 1xxx) are not included — the calculator covers the standard three-digit modes.

FAQ

What does chmod 755 mean?

Owner: read+write+execute (7); group and others: read+execute (5) — the standard mode for directories and public scripts.

What's the difference between 644 and 600?

644 lets everyone read the file while only the owner writes; 600 locks both reading and writing to the owner — right for private keys and secrets.

Why is 777 usually a bad idea?

It lets every user on the system modify the file. If a web server or another account is compromised, world-writable files become an easy target.