Chmod Calculator
Chmod Calculator — runs in your browser. Inputs are not stored.
Chmod calculator
Converts among checkboxes, octal, and symbolic mode. sticky/setuid and similar bits are not included.
How to use
- Toggle read, write, and execute for Owner, Group, and Other. The default is 755.
- If a document lists a number, type it in Octal as 755. The checkboxes follow.
- If you prefer symbolic form, enter rwxr-xr-x in Symbolic.
- Check the chmod number under Command example and Copy (chmod 755) to take it with you.
- Reset returns to the 755 default.
Key concepts
This chmod calculator maps Unix 9-bit permissions (rwxrwxrwx) among checkboxes, octal, and symbolic form. Change one and the others follow. Special bits such as setuid, setgid, and sticky are not included. The command example is a starting point; real server policy comes first.
Broad write bits on a web upload directory are risky—enable the minimum. Execute bits are needed for scripts and directory traversal and are usually off for plain text files. Conversion runs only in the browser. The model differs from Windows NTFS permissions.
Example
Turning on group write moves octal near 775 and adds w in symbolic form. Entering 644 in octal gives owner write and everyone else read. The copy button puts a chmod command with the current number on the clipboard. Keep write bits minimal on web-server upload directories and grant execute only to scripts. Editing octal updates the checkboxes, which is handy for checking a documented 755. Avoid 777 on shared hosting; treat this screen’s command example as a starting point only. When retrying the same input, reset and paste fresh so previous output does not mix in. On a shared computer, clear fields when you finish. Closing the tab drops the values; you do not need a server delete request. Button names match the tool above. If the result is empty, check required fields and hidden errors. This article is a how-to; it does not mean input is kept in external storage.
Related: htpasswd generator
Frequently asked questions
Does the chmod calculator support setuid or sticky?
Only the basic 9 bits. Special bits are not included.
Do octal and checkboxes stay in sync?
Yes. Change number, symbolic, or checks and the others update.
Is the chmod command run on a server?
No. Only a string is built; there is no remote execution.
Should I use 755 or 644?
Directories and executables often use 755; regular files 644. Choose for your environment.
How long is the symbolic form?
Nine characters such as rwxr-xr-x. There are no special-bit characters.
Does it calculate Windows permissions?
It is the Unix chmod model. ACL and NTFS are not covered.
Last reviewed: 2026-09-04