Chmod Calculator
Calculate Linux file permissions interactively. Convert between octal (755) and symbolic (rwxr-xr-x) notation with a visual checkbox grid.
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chmod
filename
| Read (4) | Write (2) | Execute (1) | Octal | |
|---|---|---|---|---|
| Owner User | 7 | |||
| Group | 5 | |||
| Others Public | 5 |
Octal
755
Symbolic
rwxr-xr-x
chmod Command
chmod 755 file
File Type
-rwxr-xr-x
Common Presets
Permission Reference
| Octal | Symbolic | Permissions | Common Use |
|---|---|---|---|
| 7 | rwx | Read + Write + Execute | Owner of directories |
| 6 | rw- | Read + Write | Owner of regular files |
| 5 | r-x | Read + Execute | Group/others for directories |
| 4 | r-- | Read only | Group/others for files |
| 3 | -wx | Write + Execute | Rarely used |
| 2 | -w- | Write only | Rarely used |
| 1 | --x | Execute only | Restricted scripts |
| 0 | --- | No permissions | Blocked access |
Related Tools
🔒
Visual Permissions
Interactive checkbox grid makes it easy to understand and set permissions for owner, group, and others. Color-coded for clarity.
⚡
Quick Presets
One-click presets for common permissions: 755 for directories, 644 for files, 600 for SSH keys, with security warnings for risky settings.
📋
Click to Copy
Click any result value to copy it instantly. Get the octal code, symbolic notation, or the full chmod command ready to paste in your terminal.
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ContactFrequently Asked Questions
What does chmod 755 mean?
chmod 755 gives the owner full permissions (read, write, execute = 7), and group and others get read and execute (5). In symbolic notation: rwxr-xr-x. This is the standard for directories and executable scripts.
What does chmod 644 mean?
chmod 644 gives the owner read and write (6), and group and others read only (4). Symbolic: rw-r--r--. This is the standard for regular files like HTML, CSS, PHP, images, and config files.
How do Linux file permissions work?
Each file has three permission groups: owner, group, and others. Each group can have read (r=4), write (w=2), and execute (x=1) permissions. Add the values together: rwx = 4+2+1 = 7, r-x = 4+0+1 = 5, r-- = 4+0+0 = 4.
What is the difference between symbolic and octal notation?
Octal uses digits 0-7 (e.g., 755) where each position is owner, group, others. Symbolic uses letters r, w, x with dashes (e.g., rwxr-xr-x). Both represent the same permissions — octal is used with chmod commands, symbolic is shown by
ls -la.Why should I avoid chmod 777?
chmod 777 gives all users full read, write, and execute permissions. This is a major security risk — any user on the system can modify, delete, or execute the file. Use 755 for directories and scripts, 644 for regular files.