Python Program for Binary To Decimal Conversion

September 28, 2022

Binary to Decimal Conversion

In this article we will discuss binary to decimal conversion in Python. For this purpose we need to take a binary integer number from user and convert that binary integer number to its decimal equivalent form and then print the converted number on to the screen. A Decimal number can be calculated by multiplying every digits of binary number with 2 to the power of the integers starts from 0 to n-1 where n refers as the total number of digits present in a binary number and finally add all of them.

Binary to decimal conversion

Working :

 A Decimal number can be calculated by multiplying every digits of binary number with 2 to the power of the integers

 starts from 0 to n-1 where n refers as the total number of digits present in a binary number and finally add all of them.

Methods Discussed :

  1. Algorithmic way (Binary to Decimal)
  2. Inbuilt Method (Binary to Decimal)

Method 1

Algorithm :

  • While num is greater then zero
  • Store the unit place value of num to a variable (rem)
  • Calculate rem with base and add it to answer
  • Completely divide Num by 10 and multiply base with 2

Time and Space Complexities

  • Time Complexity – O(N), where N is the count of the digits in the binary number
  • Space Complexity – O(1), Constant Space

Python Code :

Run 
num = 10
binary_val = num
decimal_val = 0
base = 1

while num > 0:
    rem = num % 10
    decimal_val = decimal_val + rem * base
    num = num // 10
    base = base * 2

print("Binary Number is {}\nDecimal Number is {}".format(binary_val, decimal_val))

Output :

Binary Number is 10
Decimal Number is 2

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21 comments on “Python Program for Binary To Decimal Conversion”


  • Pranudh

    num=int(input())
    decimal=0
    power=0
    while num>0:
    rem=num%10
    decimal+=rem*(2**power)
    num=num//10
    power+=1
    print(decimal)


  • Nachiket

    bin=’10001′
    sum=0
    n=len(bin)-1
    for i in range(n,-1,-1):
    sum=sum+(int(bin[i])*pow(2,i))
    print(sum)


  • Mathavan

    ls=[]
    for i in str(n):
    ls.append(i)
    k=len(ls)-1
    g=0
    i=0
    while(i<len(ls)):
    if(ls[i]=="1"):
    g+=2**k k-=1
    i+=1 print(g)


  • D

    n=input()
    s=0
    k=len(n)
    d=(2**(k-1))
    for i in (n):
    s=s+(int(i)*d)
    k-=1
    print(n,”decimal form is”,s)


  • Palak

    n = int(input())
    le = len(str(n))
    dec = 0
    l = le-1

    for i in str(n):
    dec = dec + (int(i)*(pow(2 , l)))
    l = l-1

    print(dec)


  • Saurabh

    def binary_to_deci(n):
    decimal =0
    n1 =str(n)
    for i in range(0,len(n1)):
    decimal+= (int(n1[i])*pow(2,len(n1)-1-i))
    return decimal

    n= 1001
    print(“Deciaml value of {} is”.format(n),binary_to_deci(n))


  • cherith

    n=int(input())
    l=list(str(n))
    print(l)
    l.reverse()
    print(l)
    decimal=0
    for i in range(0,len(l)):
    decimal+=int(l[i])*(2**i)

    print(decimal)


  • Asazad

    n=int(input())
    ls=[]
    for i in str(n):
    ls.append(i)
    k=len(ls)-1
    g=0
    i=0
    while(i<len(ls)):
    if(ls[i]=="1"):
    g+=2**k

    k-=1
    i+=1

    print(g)

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