← All Tools

🔒 Unix Permissions Calculator

Calculate and understand Unix/Linux file permissions (chmod).

All processing happens locally in your browser. No data is sent to any server. GDPR/DORA compliant.

Set Permissions

Read (r) Write (w) Execute (x)
Owner (u)
Group (g)
Others (o)

Special Permissions

Permission Values

Octal 644
Symbolic rw-r--r--
Binary 110 100 100
chmod Command chmod 644 filename

What These Permissions Mean

Owner (User)

Group

Others (Everyone else)

Or Enter Permission Value

Common Permission Presets

Permission Reference

Permission Bits

  • r (4) - Read
  • w (2) - Write
  • x (1) - Execute
  • - (0) - No permission

User Classes

  • u - Owner (user)
  • g - Group
  • o - Others
  • a - All (u+g+o)

Special Bits

  • SUID (4) - Run as owner
  • SGID (2) - Run as group
  • Sticky (1) - Restrict delete

chmod Examples

  • chmod 755 file
  • chmod u+x file
  • chmod go-w file
  • chmod a+r file