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Binary to Octal Conversion

In the world of computers and digital electronics, different number systems represent data. The most common ones are binary, octal, decimal, and hexadecimal. Computers understand binary, which consists of only 0s and 1s. However, humans often find it easier to read or work with octal or hexadecimal forms. 

That’s where converting binary to octal becomes useful. It simplifies long binary numbers into shorter, easier-to-read octal numbers.

 

Table Of Contents

 

What Is a Binary Number?

A binary number uses only two digits: 0 and 1. Each digit represents a power of 2.

Examples:

  • 101 = 1×2² + 0×2¹ + 1×2⁰ = 5

  • 1101 = 1×2³ + 1×2² + 0×2¹ + 1×2⁰ = 13

Computers use binary to store and process data because electronic circuits understand only two states: ON (1) and OFF (0).

 

What Is an Octal Number?

An octal number uses eight digits: 0 to 7. Each digit represents a power of 8.

Examples:

  • 45₈ = 4×8¹ + 5×8⁰ = 32 + 5 = 37

  • 12₈ = 1×8¹ + 2×8⁰ = 10

Octal numbers are used as a shorthand version of binary in computing because one octal digit = 3 binary digits.

 

Why Convert Binary to Octal?

Binary numbers can get very long. For example:

Binary: 1101001011101101

This is hard to read and interpret.

Octal: 64555₈

Much shorter and easier to understand.

That’s why we convert binary to octal to make the numbers simpler for us without losing any information.

 

Binary to Octal Conversion - Step-by-Step

Here’s how binary to octal conversion works.

Step 1: Group the binary digits in sets of 3 (from right to left)

  • If the last group has less than 3 digits, add zeros at the beginning.

Step 2: Convert each group of 3 into its octal equivalent

Use this chart for reference:

 

Binary

Octal

000

0

001

1

010

2

011

3

100

4

101

5

110

6

111

7

 

Step 3: Combine all the octal digits

This gives the final binary to octal number.

 

Example 1: Convert 10101 (binary) to octal

Step 1: Group the digits in sets of 3 (from right)

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CopyEdit

10101 → 010 101 (add a zero in front)

Step 2: Convert each group:

  • 010 → 2

  • 101 → 5

Final Answer: 25₈

 

Example 2: Convert 10010110 (binary) to octal

Step 1: Group:

CopyEdit

10010110 → 010 010 110

Step 2:

  • 010 → 2

  • 010 → 2

  • 110 → 6

Final Answer: 226₈

 

Example 3: Convert 11001 (binary) to octal

Step 1: Group:

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CopyEdit

11001 → 011 001 (add one zero in front)

Step 2:

  • 011 → 3

  • 001 → 1

Final Answer: 31₈

 

Example 4: Convert 110011 (binary) to octal

Step 1: Group:

CopyEdit

110011 → 110 011

Step 2:

  • 110 → 6

  • 011 → 3

Final Answer: 63₈

 

Octal to Binary Conversion

The reverse process is also easy. Just convert each octal digit to a group of 3 binary digits.

Example: Convert 75₈ to binary

Step 1: Convert each digit:

  • 7 → 111

  • 5 → 101

Final Answer: 111101 (binary)

Example: Convert 324₈ to binary

  • 3 → 011

  • 2 → 010

  • 4 → 100

Final Answer: 011010100

 

Binary to Octal Converter

If you want to skip manual steps, use a binary to octal converter online.

How it works:

  • Enter your binary number.

  • The converter groups and translates digits.

  • You get the octal number instantly.

These tools are handy for large numbers or quick checking.

 

Comparison: Binary vs. Octal

 

Feature

Binary

Octal

Base

2

8

Digits used

0, 1

0-7

Length

Long

Shorter

Easy for computers?

Yes

No

Easy for humans?

No

Yes

 

Applications in Real Life

  • Digital Electronics: Chips and circuits use binary and sometimes octal.

  • Computer Programming: Permissions in UNIX/Linux are shown in octal.

  • Color codes: Binary and octal systems are used in machine-level language and display codes.

  • Memory Addressing: Simplified with octal in older computing systems.

 

Common Mistakes to Avoid

  • Not padding zeros when needed (always make groups of 3)

  • Converting left to right instead of right to left

  • Using wrong binary-octal mapping

  • Skipping digits in large binary numbers

 

Fun Facts

  • Every octal digit represents exactly 3 binary digits.

  • Binary was first described by Indian mathematician Pingala in 300 BC!

  • Octal system was widely used in early computers like the PDP-8.

 

Conclusion

Understanding binary to octal conversion helps you simplify long binary strings and read them more easily. Whether you're working in programming, electronics, or just exploring number systems, this skill is practical and fun to learn.

You now know how to:

  • Convert binary to octal step by step

  • Convert octal back to binary

  • Use binary to octal converter tools

  • Avoid common mistakes

So next time you see a long binary number, you’ll know how to break it down quickly into octal!

 

Related Topics 

Binary number system -  Learn how the binary number system works using only 0s and 1s. Explore its role in computers with simple explanations and fun examples!

Irrational Numbers - Explore the World of Irrational Numbers! Discover non-repeating, non-terminating numbers like √2 and π with easy explanations and real-life examples.

Frequently Asked Questions on Binary to Octal Conversion

1. How to convert from binary to octal?

Ans: Group the binary digits into sets of 3 from the right, then convert each group using a binary-to-octal chart. For example, 101001 becomes 101 and 001 → 5 and 1 → 51₈.

 

2. How to convert 10101 binary to octal?

Group it: 010 101 → 2 5

Answer: 25₈

 

3. How to convert 10010110 binary to octal?

Group it: 010 010 110 → 2 2 6

Answer: 226₈

 

4. How to convert 11001 binary to octal?

Group it: 011 001 → 3 1

Answer: 31₈

 

5. What is 110011 binary to octal?

Group it: 110 011 → 6 3

Answer: 63₈

 

Explore more exciting math concepts with Orchids The International School!

 

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