Modern computation is based on numbers. For the most part, computers utilize the binary (base-2) system, but people use the decimal (base-10) system. Programmers, tech aficionados, and students alike must be able to convert decimal values to binary. This article will teach us the exact steps involved in converting decimals to binary, along with typical examples and practical uses, all presented in an easy-to-understand, student-friendly way.
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The process of converting numbers from one base (such as decimal) to another (such as binary) is known as number system conversion. In computer science, where the binary number system is used to process information, this is particularly crucial.
Digits used are 0 to 9
Each digit’s place value is a power of 10
Example: 453 = (4 × 10²) + (5 × 10¹) + (3 × 10⁰)
Uses only two digits: 0 and 1
Each digit’s place value is a power of 2
Example: 1011 = (1 × 2³) + (0 × 2²) + (1 × 2¹) + (1 × 2⁰) = 8 + 0 + 2 + 1 = 11
Here’s how to convert any whole number from decimal to binary:
Divide the decimal number by 2
Record the remainder (0 or 1)
Divide the quotient by 2 again, and record the next remainder
Repeat until the quotient becomes 0
Write the remainders in reverse order - that’s your binary number
Step |
Divide By 2 |
Quotient |
Remainder |
1 |
13 ÷ 2 |
6 |
1 |
2 |
6 ÷ 2 |
3 |
0 |
3 |
3 ÷ 2 |
1 |
1 |
4 |
1 ÷ 2 |
0 |
1 |
Binary = Reverse of remainders = 1101
So, 13 (decimal) = 1101 (binary)
Step |
Divide By 2 |
Quotient |
Remainder |
1 |
45 ÷ 2 |
22 |
1 |
2 |
22 ÷ 2 |
11 |
0 |
3 |
11 ÷ 2 |
5 |
1 |
4 |
5 ÷ 2 |
2 |
1 |
5 |
2 ÷ 2 |
1 |
0 |
6 |
1 ÷ 2 |
0 |
1 |
Binary = 101101
So, 45 (decimal) = 101101 (binary)
Decimal |
Binary |
1 |
1 |
2 |
10 |
3 |
11 |
4 |
100 |
5 |
101 |
6 |
110 |
7 |
111 |
8 |
1000 |
9 |
1001 |
10 |
1010 |
11 |
1011 |
12 |
1100 |
13 |
1101 |
14 |
1110 |
15 |
1111 |
16 |
10000 |
17 |
10001 |
18 |
10010 |
19 |
10011 |
20 |
10100 |
Mistake |
Correction Tip |
Forgetting to reverse remainders |
Always write remainders bottom to top |
Stopping before the quotient is 0 |
Continue until the quotient becomes 0 |
Misaligning steps |
Use a clear table for accuracy |
Confusing place values |
Remember: Binary is base-2 |
Instructions: Convert each decimal number to its binary equivalent. Show your steps clearly using the division-by-2 method.
Convert 5 to binary.
Convert 9 to binary.
Convert 12 to binary.
Convert 15 to binary.
Convert 18 to binary.
Convert 25 to binary.
Convert 37 to binary.
Convert 50 to binary.
Convert 63 to binary.
Convert 75 to binary.
Convert 100 to binary.
Convert 128 to binary.
Convert 156 to binary.
Convert 200 to binary.
Convert 255 to binary.
Convert 512 to binary.
Convert 768 to binary.
Convert 1023 to binary.
Convert 2048 to binary.
Convert 4096 to binary.
Below are detailed examples showing how the decimal to binary converter works using the division-by-2 method.
Example 1: Convert 5 to Binary
Step 1: 5 ÷ 2 = 2, remainder = 1
Step 2: 2 ÷ 2 = 1, remainder = 0
Step 3: 1 ÷ 2 = 0, remainder = 1
Binary = 101 (Write remainders in reverse order)
Example 2: Convert 9 to Binary
Step 1: 9 ÷ 2 = 4, remainder = 1
Step 2: 4 ÷ 2 = 2, remainder = 0
Step 3: 2 ÷ 2 = 1, remainder = 0
Step 4: 1 ÷ 2 = 0, remainder = 1
Binary = 1001
Example 3: Convert 25 to Binary
Step 1: 25 ÷ 2 = 12, remainder = 1
Step 2: 12 ÷ 2 = 6, remainder = 0
Step 3: 6 ÷ 2 = 3, remainder = 0
Step 4: 3 ÷ 2 = 1, remainder = 1
Step 5: 1 ÷ 2 = 0, remainder = 1
Binary = 11001
Example 4: Convert 100 to Binary
Step 1: 100 ÷ 2 = 50, remainder = 0
Step 2: 50 ÷ 2 = 25, remainder = 0
Step 3: 25 ÷ 2 = 12, remainder = 1
Step 4: 12 ÷ 2 = 6, remainder = 0
Step 5: 6 ÷ 2 = 3, remainder = 0
Step 6: 3 ÷ 2 = 1, remainder = 1
Step 7: 1 ÷ 2 = 0, remainder = 1
Binary = 1100100
Scenario: Digital Image Storage
Let’s say you take a photo using your smartphone. Each pixel in that photo is stored using numbers, and these numbers represent colors. Suppose one pixel has a grayscale value of 200 in decimal.
To store this information digitally, your phone needs to convert that decimal number (200) into binary, because computers only understand binary (0s and 1s).
Decimal to Binary is a required part to know in maths. Basically, these are two different number systems. Converting decimal numbers to binary is not just a classroom skill — it's a foundational tool in technology and engineering. Number system clears out the computer language problems easily. By learning simple methods and practicing regularly, you’ll master this essential concept with ease. Whether you're preparing for exams, coding in Python, or exploring computer science, this guide will help you every step of the way.
As computers understand only binary (0s and 1s), so decimal numbers need to be converted for processing and storage.
Divide repeatedly by 2:
100 ÷ 2 = 50, R = 0
50 ÷ 2 = 25, R = 0
25 ÷ 2 = 12, R = 1
12 ÷ 2 = 6, R = 0
6 ÷ 2 = 3, R = 0
3 ÷ 2 = 1, R = 1
1 ÷ 2 = 0, R = 1
Reverse remainders: 1100100
So, 100 (decimal) = 1100100 (binary)
Software Engineering
Data Science
Electronics Engineering
Network Security
Robotics and Automation
For decimal fractions (like 12.625), convert the integer and fractional parts separately.
12 = 1100
0.625 = (0.101)₂ (multiply by 2 repeatedly)
So, 12.625 = 1100.101
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