Octal to Decimal Converter

Convert between octal (base-8) and decimal (base-10) number systems

How to Convert Octal to Decimal

  1. Enter an octal number (digits 0-7)
  2. Click "Convert to Decimal"
  3. View the decimal equivalent
  4. Or enter a decimal number to convert to octal

Octal Number System Basics

The octal system is a base-8 number system using digits 0-7. Each digit represents a power of 8.

Common Octal Conversions

10 (octal)

= 8 (decimal)

20 (octal)

= 16 (decimal)

100 (octal)

= 64 (decimal)

177 (octal)

= 127 (decimal)

Practical Applications

  • Unix/Linux file permission systems
  • Legacy computer systems programming
  • Digital electronics and microcontroller programming
  • Computer science education
  • Debugging low-level systems

Conversion Formula

decimal = d0×80 + d1×81 + d2×82 + ...

Where dn is the octal digit at position n

Octal Number Characteristics

  • Base-8 number system
  • Each digit represents exactly 3 binary digits (bits)
  • Commonly used in Unix file permissions (e.g., chmod 755)
  • More compact than binary representation