Chmod Calculator
Calculate Linux file permissions with a visual checkbox interface. Generates octal and symbolic notation.
How Chmod Works
Each permission has a numeric value:
- Read (r) = 4
- Write (w) = 2
- Execute (x) = 1
The total for each group is the sum of the active permissions:
- Owner: The file creator/owner
- Group: Users in the file's group
- Public: Everyone else
Example: Owner has r+w+x (4+2+1=7), Group has r+x (4+0+1=5), Public has r+x (4+0+1=5) = 755
Read
Write
Execute
Owner
Group
Public
Octal: 755
Symbolic: rwxr-xr-x
Common Presets
Examples of use
- Calculate permissions for a web server directory (755)
- Set secure file permissions for SSH keys (600)
- Generate chmod commands for deployment scripts
When to use this tool?
- When setting file permissions on Linux/Unix systems
- When debugging permission-related issues on servers
- When writing deployment or CI/CD scripts that need chmod commands
Frequently asked questions
- What do the octal numbers mean?
- Each digit represents permissions for Owner, Group, and Public respectively. 4=read, 2=write, 1=execute. For example, 755 means Owner has rwx (7), Group has r-x (5), and Public has r-x (5).
- What is the difference between octal and symbolic notation?
- Octal uses numbers (e.g., 755), while symbolic uses letters (e.g., rwxr-xr-x). Both represent the same permissions but in different formats.