Convert Decimal to Binary

Convert a non-negative integer from decimal to binary representation.

BeginnerTopic: Basic Python Programs

What You'll Learn

Using loops and modulo for base conversion
Building strings from lists of digits
Understanding how binary representation works

Python Convert Decimal to Binary Program

This program helps you to learn the fundamental structure and syntax of Python programming.

# Program to convert decimal to binary without using bin()

num = int(input("Enter a non-negative integer: "))

if num < 0:
    print("Please enter a non-negative integer.")
elif num == 0:
    print("Binary: 0")
else:
    binary_digits = []
    n = num
    while n > 0:
        remainder = n % 2
        binary_digits.append(str(remainder))
        n //= 2

    binary_digits.reverse()
    binary_str = ''.join(binary_digits)
    print(f"Binary of {num} is {binary_str}")

Output

Enter a non-negative integer: 10
Binary of 10 is 1010

Step-by-Step Breakdown

1Read a non-negative integer.
2Loop while the temporary value is > 0.
3Append each remainder (n % 2) to a list.
4Reverse and join the list into a string.
5Print the final binary string.

Understanding Convert Decimal to Binary

We repeatedly divide the number by 2, collecting remainders:

1.Take remainder of division by 2 → least significant bit.

2.Divide by 2 using integer division.

3.Repeat until the number becomes 0.

4.Reverse the collected bits to get the correct order.

This demonstrates a classic base conversion algorithm.

Note: To write and run Python programs, you need to set up the local environment on your computer. Refer to the complete article Setting up Python Development Environment. If you do not want to set up the local environment on your computer, you can also use online IDE to write and run your Python programs.

Convert Binary to Decimal