Chmod Calculator
Calculate Unix file permission values visually. Toggle read, write and execute for owner, group and others — get the octal value and symbolic string instantly.
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Free
Browser-based
744
Octal
rwxr--r--
Symbolic
chmod 744
Command
Understanding Unix File Permissions
Unix and Linux systems control file access with three permission sets — Owner (the file creator), Group (users in the assigned group) and Others (everyone else). Each set has three bits: Read (4), Write (2) and Execute (1). Adding the bits gives the octal digit for that set.
Common Permission Values
| Octal | Symbolic | Typical use |
|---|---|---|
| 755 | rwxr-xr-x | Web-accessible directories, scripts |
| 644 | rw-r--r-- | Regular files, HTML, CSS |
| 600 | rw------- | Private files, SSH keys |
| 700 | rwx------ | Private directories |
| 777 | rwxrwxrwx | Fully open (avoid in production) |
| 664 | rw-rw-r-- | Shared group-editable files |
Execute Bit on Directories
For directories, the execute bit means traversal — the ability to enter the directory or access files inside it. A directory with r-- (read but no execute) lets you list its contents but not access the files. Most directories should have the execute bit set for any entity that needs to enter them.