Binary to Octal Converter — How to Convert Binary to Octal

Why binary-to-octal conversion works.

Octal is base-8 and binary is base-2. The simple conversion comes from one fact: 8 = 2³. Because 8 is exactly the third power of 2, exactly 3 binary digits represent all 8 possible octal values (0–7). No arithmetic is required — just a direct one-to-one group substitution.

How to convert a binary to octal number (Step-by-step).

1. Write the binary number. Example: 11010110
2. Group from the right in triplets, padding left as needed:
   11010110 → [011] [010] [110]
3. Convert each group: 011=3, 010=2, 110=6
4. Concatenate: → 326₈

Worked examples.

How to convert a binary fraction to octal.

Converting a binary number with a decimal point (a binary fraction) to octal requires splitting the number into two parts: the integer part and the fractional part. Group the integer part from right-to-left, and group the fractional part from left-to-right. Pad with zeros as necessary.

Binary to octal in code.

print(format(int("11010110", 2), 'o'))  # Output: 326
print(format(int("101010", 2), 'o'))    # Output: 52
print(oct(int("11111111", 2))[2:])      # Output: 377

const toOct = b => parseInt(b, 2).toString(8);
console.log(toOct("11010110")); // "326"
console.log(toOct("101010"));   // "52"

#include <stdio.h>
#include <stdlib.h>
int main() {
    long d = strtol("11010110", NULL, 2);
    printf("%lo\n", d);  // 326
    return 0;
}

System.out.println(
  Integer.toOctalString(Integer.parseInt("11010110", 2))
); // "326"