Chmod Permissions Calculator
Convert Linux file permissions between octal (755) and symbolic (rwxr-xr-x), including setuid, setgid and sticky bits, and copy the chmod command.
Examples: 755, 0644, 4755, rwxr-xr-x, -rw-r--r--, rwsr-xr-t
| Read | Write | Execute | Special bit | |
|---|---|---|---|---|
| Owner (u) | ||||
| Group (g) | ||||
| Others (o) |
| Octal | 644 |
|---|---|
| Symbolic | rw-r--r-- |
| As shown by ls -l (file) | -rw-r--r-- |
| chmod command | chmod 644 file |
| chmod with symbolic mode | chmod u=rw,g=r,o=r file |
- Owner (u): read, write
- Group (g): read
- Others (o): read
What is Chmod Calculator?
The chmod calculator converts Unix file permissions between octal notation (644, 755, 4755) and symbolic notation (rw-r--r--, rwsr-xr-x), including the setuid, setgid and sticky special bits. Tick read, write and execute for owner, group and others, and it builds both the numeric and the symbolic chmod command.
How to use Chmod Calculator
- Type a mode such as
755,0644,4755,rwxr-xr-xor-rw-r--r--, or tick the checkboxes. - Use the preset buttons for common modes like 644, 755, 600 or 1777.
- Read the octal and symbolic forms, the ls -l view and the chmod commands.
- Check the plain-language summary and warnings, e.g. for world-writable files.
Example
rwsr-xr-t
Octal 5755 · ls -l: -rwsr-xr-t · chmod u=rwxs,g=rx,o=rxt file
755 is rwxr-xr-x, chmod u=rwx,g=rx,o=rx file.
When to use Chmod Calculator
Use it when setting permissions on web servers, scripts, SSH keys or shared directories, or to read a mode shown by ls -l or stat. It does not change files – run the generated command yourself – and it does not cover ACLs or the umask.
How Chmod Calculator works
Each class (owner, group, others) is three bits: read 4, write 2, execute 1, so rwx = 7 and r-x = 5. An optional fourth leading octal digit holds the special bits: setuid 4, setgid 2, sticky 1. In symbolic form a special bit replaces the execute character with s/S (owner, group) or t/T (others); lowercase means execute is also set, uppercase means it is not. A 10-character ls -l string is accepted by ignoring the file-type character.
Common Use Cases
- Find the octal for rwxr-x--- (750) for a deployment script.
- Set an SSH private key to 600.
- Understand what the t in drwxrwxrwt on /tmp means.
- Translate 2775 into symbolic form for a shared group directory.
FAQs
What does chmod 755 mean?
Owner can read, write and execute (7); group and others can read and execute (5). It is typical for directories and executable scripts.
What do capital S and T mean?
The setuid/setgid or sticky bit is set while the execute bit for that class is not – usually a mistake for executables.
What does execute mean on a directory?
Permission to enter the directory and access files inside by name. Read on a directory only allows listing names.