Numeric chmod--
Symbolic string--
Chmod Permission Calculator
Convert Linux file permissions into numeric chmod values and symbolic strings. This helps when setting web files, scripts, SSH keys, and server permissions.
Updated May 2026No signup requiredBuilt for mobile
How to use this calculator
Enter the real measurements or counts you have now, run the calculator, then round the result in the practical direction before buying supplies or making a plan.
Formula or calculation method
Read = 4, write = 2, execute = 1
Owner digit = owner read + owner write + owner execute
Group digit = group read + group write + group execute
Others digit = others read + others write + others execute
Practical examples
Example 1
644 means owner can read/write, while group and others can read.
Example 2
755 means owner can read/write/execute, while group and others can read/execute.
Useful assumptions
- This covers basic Unix-style read, write, execute permissions.
- It does not include ACLs, SELinux, sticky bits, setuid, or setgid.
- For servers, use the least permission needed.
Common mistakes
- Making private files world-readable
- Setting executable permission on files that do not need it
- Using 777 as a shortcut
- Forgetting directory execute permission controls traversal
FAQ
Chmod Permission Calculator questions
What does chmod 755 mean?
Owner has read, write, and execute. Group and others have read and execute.
What does chmod 644 mean?
Owner has read and write. Group and others have read only.
Is chmod 777 safe?
Usually no. It gives everyone read, write, and execute permission.
Why do directories need execute permission?
Directory execute permission allows traversal into the directory.
Does this include ACLs?
No. It covers basic owner, group, and others permissions.