Octal to Binary Converter

What is Octal to Binary Converter?

Paste an octal (base 8) number and get its binary equivalent instantly, useful when working between two low-level number representations without going through decimal by hand. Conversion runs live in your browser as you type, using arbitrary-precision math, so long octal values convert exactly without a fixed-width limit.

Octal to Binary Table

How to Use the Octal to Binary Converter

1. 1

   Paste or Type an Octal Number: Enter digits 0-7 only, such as 17 or 42.

2. 2

   Read the Binary Result Instantly: The binary equivalent appears automatically as you type, with no button to click.

3. 3

   Copy the Result: Use the copy button to copy the binary string for use in code or coursework.

Octal and Binary Place Values

Both octal (base 8) and binary (base 2) are positional number systems where each digit's value depends on its position, just like decimal. Octal digits only run 0-7, though, and binary digits only run 0-1. Because 8 is a power of 2 (8 = 2³), every single octal digit converts to exactly 3 binary digits. That makes octal a convenient shorthand for binary: three bits packed into one digit.

How to Convert Octal to Binary

Convert each octal digit to its 3-bit binary form individually, then concatenate the results. There's no need to convert the whole number through decimal first. For example, converting octal 17: 1 → 001, 7 → 111. Joined together and with the leading zero dropped: 1111, which is decimal 15 confirmed above in the table. For a multi-digit example, octal 42: 4 → 100, 2 → 010, giving 100010.

Octal to Binary Examples

Octal 10 (decimal 8) → binary 1000: digit 1 → 001, digit 0 → 000, joined and leading zeros trimmed gives 1000. Octal 7 (decimal 7) → binary 111: a single digit, so it's just that digit's 3-bit form with leading zeros dropped. Octal 15 (decimal 13) → binary 1101: digit 1 → 001, digit 5 → 101, joined as 001101, leading zeros trimmed to 1101.