Octal to Binary Converter: Your Quick Conversion Tool

How the conversion works

The tool goes through decimal as an intermediate step: it parses your octal input as base 8 (parseInt(input, 8)), then converts that decimal value to a binary string (.toString(2)). Enter 17 and it first computes the decimal value 15 (1×8 + 7×1), then outputs Binary: 1111.

Input rules

Octal only uses digits 0-7 — an 8 or 9 isn't valid in base 8, and the regex check (/^[0-7]+$/) rejects them along with letters and symbols, showing "Please enter a valid octal number (using digits 0-7 only)" instead of a wrong result.

Reference values

Octal is grouped in sets of 3 binary digits (since 2³ = 8), which is why it was historically used as shorthand for binary on systems with word sizes divisible by 3, before hexadecimal (grouped in sets of 4) became the more common shorthand.