How do I get the chmod number for rwxr-xr-x?

Tick the Read, Write and Execute boxes for Owner, Group and Other. The Octal value updates live, 755 for rwxr-xr-x, and the Command section gives the full chmod command to copy.

How do I convert a permission number like 644 into read, write and execute?

Type 644 into the Octal (editable) field. The checkboxes and Symbolic notation update to match: owner read and write, group and other read only. Each digit sums read 4, write 2 and execute 1.

Can I paste the permissions from an ls -l listing?

Yes. Paste a string such as -rwxr-xr-x into Paste ls -l permissions and the checkboxes, octal and symbolic values update. If no permission string is found, it shows an error message.

How do I add the recursive flag or a filename to the command?

Type a name under Target file or folder and tick Recursive (-R). The Command output includes them. You can pick the Octal or Symbolic form. A warning appears for recursive 777.

What permissions should I use for files, folders and SSH keys?

Presets include 644 for files, 755 for dirs and scripts, 600 for private files such as SSH keys, and 700 for private folders. The 777 preset is marked as one to avoid.

Yes. Every tool is free to use, with no account and no credit card. The work runs on your device rather than on our servers, which is what keeps it free to run.

Does it work on mobile?

Yes. It runs in current mobile browsers on iOS and Android, with nothing to install.

Chmod Calculator — Unix File Permissions 755/644

Common uses

Correct File Permissions for Web ServersSet the right permissions for web files and folders on Apache/Nginx servers.
Set SSH Key PermissionsSSH refuses keys with loose permissions. Get the exact chmod for your key files.
Make Shell Scripts ExecutableGet the chmod command to make a script runnable while keeping it secure.
Learn Linux File PermissionsUnderstand how octal and symbolic Unix permissions map to read/write/execute.
File Permissions in Docker ImagesSet correct permissions for files copied into Docker containers.

How It Works

This tool is a hand-written, fully client-side Unix permissions calculator — no libraries, no server. It models each permission as a boolean in a React state matrix and converts between octal, symbolic, and ls -l formats using direct bitwise arithmetic.

1
Checkbox matrix sets state
Each of the nine read/write/execute checkboxes (owner, group, other) toggles a boolean in a React state object. Special bits — setuid, setgid, and sticky — are tracked separately in a parallel state object.
2
Bitwise arithmetic computes octal
The octalFor() function sums the active permission values for each group using the fixed weights r=4, w=2, x=1. The three group digits are concatenated, and if any special bit is set, a fourth leading digit (setuid=4, setgid=2, sticky=1) is prepended.
3
Bidirectional parsing syncs all inputs
Typing a 3- or 4-digit octal number triggers parseOctal(), which uses bitwise AND to decompose each digit back into permission booleans and update the checkbox matrix. Pasting an ls -l line triggers parseLsPerms(), which uses a regex to extract the 9-character permission string and decodes special characters like s, S, t, and T for setuid/setgid/sticky.
4
chmod command is assembled and copied
The final chmod command is built by string interpolation — octal mode or symbolic mode (u=rwx,g=rx,o=rx form) — with optional -R flag and target filename. Clicking Copy writes the command to the clipboard via navigator.clipboard.writeText(), which runs locally with no network call.

Free chmod Permissions Calculator

Common uses

How It Works

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Frequently Asked Questions

	Read	Write	Execute	Value
Owner				7
Group				5
Other				5