chmod calculator

Toggle read/write/execute for owner, group and others — get octal, symbolic and a ready chmod command.

Runs entirely in your browser — your data never leaves your device and nothing is stored. No sign-up.

Build Unix file permissions visually — tick read, write and execute for owner, group and others, and get the octal mode (like 755), the symbolic string (rwxr-xr-x) and a ready `chmod` command. Enter an octal value to update the checkboxes the other way. Optional setuid, setgid and sticky bits cover the fourth digit. Everything runs in your browser. Free, no sign-up.

✓Owner / group / others × read / write / execute
✓Octal and symbolic output together
✓Bidirectional: type 755 to sync checkboxes
✓Optional setuid, setgid and sticky bits
✓Copy octal, symbolic or the full chmod command
✓Runs locally — nothing uploaded

Who it's for

Setting script and directory permissions
Checking what a mode number means
Writing chmod commands for deploy docs
Teaching Unix permissions

How it works

1Toggle permissions for owner, group and others.
2Optionally enable special bits.
3Copy the octal mode, symbolic string or chmod command.
4Or type an octal value to drive the checkboxes.

Frequently asked questions

What does chmod 755 mean?+

Owner can read, write and execute (7); group and others can read and execute (5). In symbolic form that is rwxr-xr-x — common for executable scripts and directories.

What is the symbolic form?+

Nine characters in three groups of rwx (or -): owner, group, others. Special bits may replace x with s/S (setuid/setgid) or t/T (sticky).

When do I need setuid / setgid / sticky?+

Rarely for everyday files. setuid/setgid change effective user/group on execute; sticky on directories (like /tmp) restricts who can delete files. Enable them only when you know you need them.

Is this the same as ACL permissions?+

No — this calculator covers classic Unix mode bits only, not POSIX ACLs or macOS/Windows ACLs.

Is my data uploaded?+

No. Permission math runs entirely in your browser.