Chmod Calculator

Visually set Linux file permissions and instantly get the matching chmod octal and symbolic notation.

644

rw-r--r--

chmod 644 filename

What each permission does

read (r)

File: view the file's contents

Folder: list files inside the directory

write (w)

File: modify or delete the file

Folder: add, rename, or remove files inside

execute (e)

File: run the file as a program/script

Folder: enter (cd into) the directory

Owner is the file's creator, group is other members of the file's assigned group, and others is everyone else on the system. The octal digit for each (0–7) is read (4) + write (2) + execute (1) added together.

How to apply this on each OS

Linux

Run directly in the terminal: chmod 644 filename. Add -R to apply recursively to a whole directory, e.g. chmod -R 644 folder/.

macOS

Same command as Linux, macOS's Terminal is Unix-based, so chmod 644 filename works identically. You can also set permissions via Finder → Get Info → Sharing & Permissions, though that UI doesn't expose the execute bit.

Windows

Windows doesn't use Unix-style permissions natively, so plain chmod isn't available in Command Prompt or PowerShell. Use WSL or Git Bash to run the same command as Linux/macOS, or manage native NTFS permissions instead with icacls filename /grant User:F (full control), note this maps to a different permission model, not a direct octal equivalent.

About the Chmod Calculator

A chmod calculator converts between the visual read, write, and execute permissions you want to set and the numeric or symbolic notation the chmod command expects on Linux and macOS.

Common permission combinations

	Octal	Symbolic
755	rwxr-xr-x	Scripts and executable files
644	rw-r--r--	Regular files, readable by everyone
700	rwx------	Private files only the owner can access
777	rwxrwxrwx	Full access for everyone, generally unsafe

How to use

Check the read, write, and execute boxes for Owner, Group, and Others based on the access you want to grant.

Copy the generated octal number, such as 755, or the symbolic string, such as rwxr-xr-x.

Run it as chmod followed by the value and filename in your terminal, or apply it through your hosting control panel.

Frequently asked questions

What does chmod 755 mean?

It gives the owner full read, write, and execute access, while group and others get read and execute only, the standard setting for scripts and executable files.

Is chmod 777 safe to use?

Generally no for anything web-facing, since it gives every user on the system full read, write, and execute access, which is a common security misconfiguration.

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