Octal to Decimal Calculator

Use our free octal to decimal converter to instantly convert any octal number to decimal with full place-value expansion, binary and hex equivalents.

Math

Octal Number

Formula

Convert octal to decimal. See each octal digit multiplied by its place value (8ⁱ), the running sum, binary, and hex equivalents.

d = Σ oᵢ × 8ⁱ

Percentage: The percentage value you want to apply

Number: The original number or value

Result: The calculated result

Result: 15

Result: 255

Multiply each octal digit by 8 raised to its position (from right, starting at 0), then sum.

0, 1, 2, 3, 4, 5, 6, 7 — no 8 or 9 allowed.

Historically in computing (file permissions in Unix/Linux), and as a compact representation of binary.

CalculateMe Team

Last updated: 2026-07-15