Free online Unix/Linux file permission calculator. Convert between symbolic mode (u=rwx,g=rx,o=r) and numeric mode (755). Visual permission bit viewer with one-click command copy.
How to Use
- • Toggle the permission checkboxes to adjust permissions
- • Symbolic and numeric modes update in sync
- • Click the copy button to copy the chmod command
- • Special permission bits are only used in certain scenarios
π‘ The chmod command changes file and directory access permissions on Unix/Linux systems.
FAQ
What does chmod 755 mean?
755 is the numeric representation of file permissions in Unix/Linux. 7 (rwx) means the owner has read, write and execute; 5 (r-x) means the group and others have read and execute only. This is standard for web server files.
How to convert between symbolic and numeric modes?
Symbolic mode like u=rwx,g=rx,o=r maps to numeric 754. Calculation: r=4, w=2, x=1. Owner: 4+2+1=7, Group: 4+0+1=5, Others: 4+0+0=4.
What are common file permissions?
Common permissions include: 644 (default file, rw-r--r--), 755 (default dir/script, rwxr-xr-x), 700 (private, rwx------), 777 (fully open, rwxrwxrwx, not recommended), 600 (private file, rw-------).
Does chmod support special permissions?
Besides basic permissions, chmod supports SUID (4xxx), SGID (2xxx) and Sticky Bit (1xxx) special permissions. For example, chmod 4755 sets the SUID bit so the program runs with the owner's privileges.
What is the Chmod Calculator?
The Chmod Calculator is a free online tool that runs entirely in your browser. Convert between numeric and symbolic chmod notation and understand read/write/execute permissions for every user class.
Use Cases
- Check correct permissions before deploying web files
- Convert symbolic mode like u=rwx,g=rx,o=r to numeric 754
- Verify SUID, SGID and sticky bit configurations
- Learn Unix/Linux permission math quickly
Key Features
- Completely Free: No registration, no limits
- Privacy Safe: Data never leaves your browser
- Cross-Platform: Any modern browser
- Zero Dependencies: Open and use