Octal to Binary Converter

An octal to binary converter turns an octal number into binary, the 0 and 1 code that computers use. Octal uses digits from 0 to 7, and each octal digit stands for exactly three binary digits, because 2 to the power of 3 equals 8.

That grouping is why octal was once a popular shorthand for binary, and why it still appears in file permissions and computing study. This tool converts each octal digit to its three bit group and joins them, so you get the full binary value with no rounding and no sign up.

Everything runs in your browser, so your number never leaves your device. The tool is useful for homework, coding and checking older code that uses octal values.

Worked example: octal 52 to binary

Split 52 into its two octal digits: 5 and 2.

Convert each digit to three bits: 5 is 101, and 2 is 010.

Join the groups in order: 101010. So 52 in octal is 101010 in binary.

You can check the answer by place value: 52 in octal is 42 in decimal, and 32 plus 8 plus 2 equals 42.

How to Use This Tool

1. Enter an octal number using digits 0 to 7 only.
2. Press Convert to see the binary result and the three bit groups.
3. Copy the result or download it as a text file.
4. Use Load Sample to try 52, which converts to 101010.

Why Use This Tool

• Exact for long octal values, with no rounding and no sign up.
• Shows the three bit group for each digit, so the answer is easy to verify.
• Rejects digits 8 and 9 with a plain error message.
• Private by design, since nothing leaves your device.

Common Values

Related Conversions

If you need a different direction, try the Octal to Decimal Converter, Octal to Hex Converter, Binary to Octal Converter and Decimal to Octal Converter. Each one works the same way, in your browser, with the steps shown so you can check the answer.

Frequently Asked Questions