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Octal to Binary Converter

Convert octal numbers to binary (base 2) instantly, one digit to three bits. Each octal digit expands to exactly three binary bits.

Octal Digit to Binary Bits

0000
1001
2010
3011
4100
5101
6110
7111

How to Convert Octal to Binary

Since 8 = 2³, converting octal to binary is a direct per-digit lookup with no arithmetic:

  1. Take each octal digit one at a time
  2. Replace it with its 3-bit binary equivalent
  3. Keep leading zeros inside each group so every digit is 3 bits
  4. Join the groups in order to get the full binary number

Example: Convert 32 to binary:

  • 3 → 011
  • 2 → 010
  • Result: 011010, or 11010 without the leading zero

Code Examples

const octal = "32";
parseInt(octal, 8).toString(2); // "11010"

Frequently Asked Questions

How do I convert octal to binary?

Replace each octal digit with its 3-bit binary equivalent: 0=000, 1=001, 2=010, 3=011, 4=100, 5=101, 6=110, 7=111. For example, 32 becomes 011 010 = 11010.

Why does each octal digit map to 3 bits?

Octal is base 8 and 8 = 2³, so every octal digit represents exactly three binary bits. That is why the conversion is a simple per-digit lookup with no arithmetic.

Can I enter a 0o prefix?

Yes. Plain octal like 755 and prefixed octal like 0o755 are both accepted. Only the digits 0 through 7 are valid octal input.

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