Binary To Octal Converter

2
8

Converting steps:

How to convert a binary number to the octal number?

To convert binary to octal, group the binary digits into sets of three, convert each group to its octal value, and combine the results. This works because 23 = 8, so three binary digits map to one octal digit.



Binary to Octal conversion

Example of binary to octal conversion.

Convert (10111.1011)2 to octal.

Binary =     0 1 0 1 1 1 . 1 0 1 1 0 0
Chunk =     _____ _____ . _____ _____
Arrows =        ↓    ↓ .    ↓    ↓
Octal =        2    7 .    5    4

Result is: (27.54)8

Note: Use groups of three binary digits. Add leading zeros to the left of the whole-number part or trailing zeros to the right of the fractional part when a group is incomplete.

When binary to octal is useful

Octal is less common than hexadecimal today, but it still appears in some programming, file permission, and digital logic examples. Binary to octal conversion is helpful because each octal digit represents exactly three binary digits, making long binary values easier to read and compare.

Common mistakes

  • Group binary digits in sets of three, not four.
  • For the whole-number part, start grouping from the right side.
  • For the fractional part, start grouping immediately after the decimal point.
  • Only digits 0 through 7 can appear in the octal result.

Binary to Octal conversion table

Binary Octal
0 0
1 1
10 2
11 3
100 4
101 5
110 6
111 7
1000 10
1001 11
1010 12
1011 13
1100 14
1101 15
1110 16
1111 17
10000 20
10001 21
10010 22
10011 23
10100 24

Binary to octal guide

Binary to octal conversion is easiest when you group binary digits in sets of three. Each 3-bit group maps to one octal digit from 0 to 7.

Best uses

  • Shorten long binary values for reading or documentation.
  • Practice base conversion in computer science classes.
  • Check low-level values where octal notation is used.

Quality checks

  • Group whole-number bits from right to left.
  • Add leading zeros only when needed to complete the first group.
  • For fractional values, group digits to the right after the point.

Common mistakes

  • Grouping binary digits in fours instead of threes.
  • Removing zeros inside the original number.
  • Reading octal digits as decimal place values.

Quick answers

Why use groups of three?

Three binary bits represent values from 0 to 7, which exactly matches one octal digit.

Can I add zeros before a binary number?

Yes, leading zeros do not change the value and can make the first group complete.