Developer Tool
Chmod Calculator
Convert Unix file permissions between numeric, symbolic, and command formats. Toggle read, write, execute, setuid, setgid, and sticky bits, then copy a safe chmod command.
Avoid broad permissions like 777 on shared servers. Use recursive chmod only after checking every nested path.
Permission grid
Toggle read, write, and execute for owner, group, and others.
3 digits set normal permissions. 4 digits add setuid, setgid, or sticky bit.
Presets
Current mode
755
Common for directories and executable scripts.
Symbolic
rwxr-xr-x
Numeric
755
Command
chmod 755 path/to/file
Who can do what
Privacy
This tool runs entirely in your browser. Paths and generated commands are not sent anywhere.
Numeric mode
Read is 4, write is 2, execute is 1. Each digit is the sum for owner, group, and others.
Symbolic mode
rwxr-xr-x is the symbolic form of 755. Special bits appear as s, S, t, or T.
Local only
The target path and generated chmod command stay in your browser.
Common chmod examples
Regular file
Owner can write. Group and others can read. Common for text files and web assets.
Directory or executable
Owner can write. Everyone can enter or execute. Common for directories and scripts.
Private secret
Owner read/write only. Common for SSH private keys and local config files.
Sticky shared directory
World writable, but users cannot delete files owned by others. Common for /tmp style directories.
よくある質問
What does chmod 755 mean?
755 means owner can read, write, and execute; group and others can read and execute. It is common for directories and executable scripts.
What is safer for private files?
Use 600 for private files such as SSH keys, and 700 for private directories or scripts that only the owner should access.
Should I use chmod 777?
Avoid chmod 777 unless you have a very specific reason. It gives everyone read, write, and execute permission, which is risky on shared systems.
Are generated paths or commands stored?
No. The calculator runs locally in your browser and does not send the target path or generated chmod command anywhere.