Binary to Decimal Converter

Convert binary numbers (0s and 1s) to decimal with our step-by-step calculator. Learn the positional value method, see detailed examples, and understand how computers store numbers.

Calculation Steps

What is Binary?

Binary is a base-2 number system that uses only two digits: 0 and 1. It's the foundation of all modern computing because computers use electrical circuits that can be either on (1) or off (0). Understanding binary helps you understand how computers work at the most basic level.

Each digit in a binary number is called a "bit" (short for binary digit). Eight bits make a "byte", which can represent 256 different values. When you see numbers like 1011 or 11001, you're looking at binary numbers that computers understand perfectly but humans find challenging to read.

Binary position values: ... 16 8 4 2 1

The rightmost position has value 1, then 2, then 4, then 8, and so on (each double the previous value). To understand what a binary number means, you add up the values of positions that have a 1.

Step-by-Step Conversion Method

The most common method for converting decimal to binary is the division-by-2 method. Here's exactly how it works:

  1. Start with your decimal number - Let's convert 45 to binary as an example
  2. Divide by 2 - 45 ÷ 2 = 22 with remainder 1
  3. Write down the remainder - The remainder (1) becomes the rightmost digit of your binary answer
  4. Divide the quotient by 2 - Take the result (22) and divide by 2: 22 ÷ 2 = 11 remainder 0
  5. Write down this remainder - This becomes the next digit to the left
  6. Repeat until quotient is 0 - Keep dividing until you get a quotient of 0
  7. Read remainders backwards - The binary number is the remainders read from bottom to top

Complete example: Convert 45 to binary

45 ÷ 2 = 22 remainder 1 (least significant bit)

22 ÷ 2 = 11 remainder 0

11 ÷ 2 = 5 remainder 1

5 ÷ 2 = 2 remainder 1

2 ÷ 2 = 1 remainder 0

1 ÷ 2 = 0 remainder 1 (most significant bit)

Binary result: Read from bottom to top: 101101

So 45 in decimal = 101101 in binary

Our converter above does all these steps automatically and shows you each step so you can learn how it works.

Why Learn Decimal to Binary?

Learning decimal to binary conversion has practical benefits:

Common Decimal to Binary Conversions

Here are some common decimal numbers and their binary equivalents. Try converting them with our tool:

DecimalBinaryInteresting Fact
00Same in both systems
11Also the same
210First "carry" in binary
311All 1s in two bits
41002 squared (2²)
810002 cubed (2³)
101010Decimal 10 in binary
16100002 to the 4th power (2⁴)
321000002 to the 5th power (2⁵)
6410000002 to the 6th power (2⁶)
1001100100One hundred in binary
25511111111Maximum value for 8 bits

Try converting your age, birth year, or favorite number to binary using our converter!

Binary in Everyday Technology

Binary numbers are everywhere in modern technology:

Understanding binary helps you understand how all these technologies work at a basic level.

Tips for Learning Decimal to Binary

Here are tips to help you master decimal to binary conversion:

With practice, you'll be able to convert decimal to binary quickly and easily!