How to convert Octal to Decimal

Conversion factor and calculation steps from Octal (oct) to Decimal (dec).

Conversion logic

The number is first converted to decimal as digits × radixⁿ, then to the selected base by division with remainder. Prefixes 0x, 0b, 0o and digit grouping with spaces or _ are allowed.

oct: digits 0 1 2 3 4 5 6 7, radix 8

dec: digits 0 1 2 3 4 5 6 7 8 9, radix 10

255₈ = 2×8₂ + 5×8₁ + 5×8₀ = 128 + 40 + 5 = 173₁₀

255₈ = 173₁₀