Chmod Calculator Online Free
Calculate Linux file permissions instantly using octal and symbolic notation. Check boxes for Owner, Group, and Public scopes to generate standard terminal chmod commands.
✓ Free IT tool✓ No signup required✓ Fast results✓ Browser-based utility✓ Mobile friendly
Read (r)
Write (w)
Execute (x)
Owner
Group
Others
644
Octal
rw-r--r--
Symbolic
Commands
chmod 644 filenamechmod u=rw,g=r,o=r filenameThis tool runs in your browser and does not upload data to BuBird servers.
How To Use
How to Use Chmod Calculator
1
Select Owner Permissions
Check permissions for the Owner: Read (r), Write (w), and/or Execute (x).
2
Select Group Permissions
Check permissions for the Group: Read, Write, and/or Execute.
3
Select Others Permissions
Check permissions for Others (Public): Read, Write, and/or Execute.
4
Copy the Chmod Code
Observe the updated octal (e.g. 755) or symbolic (e.g. -rwxr-xr-x) value and copy the generated terminal command.
Example
Example Use
Setting Executable Permissions on a Script
To make a custom script (e.g., backup.sh) readable and executable by everyone, but writable only by the Owner, select Read and Write for Owner, and Read and Execute for Group and Others. The calculator generates octal value 755 and command 'chmod 755 backup.sh'.
Use Cases
Who Uses Chmod Calculator
Linux SysAdmins
Quickly verify octal syntax when configuring server files, shell scripts, and web directories.
Web Developers
Troubleshoot hosting permission errors (e.g., 403 Forbidden) by setting correct directory flags.
DevOps Engineers
Define permissions inside Dockerfiles, CI/CD scripts, and deployment packages.
IT Students
Learn octal addition logic (4+2+1) and symbolic notation formats.
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FAQ
Frequently Asked Questions
What is chmod?
chmod (change mode) is a Linux/Unix terminal command used to alter access permissions for file system objects (files and directories).
What do the numbers in a chmod code mean?
The numbers represent octal values for Owner, Group, and Public scopes. Each number is calculated by adding permissions: Read (4), Write (2), and Execute (1).
Does this tool upload my configuration?
No. The chmod calculator executes calculations locally in your web browser using JavaScript.