About This Converter
Convert octal (base 8) numbers to decimal (base 10) using positional weight multiplication. Enter an octal number like 377 and see the decimal result (255) with each power-of-8 calculation shown. Commonly needed for Unix permissions, embedded systems, and computer science exams.
Worked Examples
Octal: 377 → Decimal: 255
3×64 + 7×8 + 7×1 = 192+56+7 = 255
Octal: 755 → Decimal: 493
7×64 + 5×8 + 5×1 = 448+40+5 = 493 (common chmod value)
Octal: 10 → Decimal: 8
1×8 + 0×1 = 8 (octal 10 = decimal 8)
Need More Bases?
For full multi-base conversion (binary, octal, decimal, and hex all at once), use our Number System Converter — it shows all four representations simultaneously with complete step-by-step working.