Hexadecimal to Decimal Conversion in Python

September 29, 2022

Hexadecimal to Decimal Conversion

On this page we will learn how to create a python program for Hexadecimal to Decimal Conversion.

Hexadecimal has numbers in the range of [0, 15] and to achieve so it also uses some characters of alphabets.

Hexadecimal Working :

As discussed in hexadecimal numbers range from 0 to 15 so 0 to 9 are represented same as integer values but after 9 alphabets are used as shown below :

A = 10
B = 11
C = 12
D = 13
E = 14
F = 15

How To Convert From Hexadecimal to Decimal Manually?

For a user input num. This requires you to know ASCII values, please check the ASCII table here

To convert a hexadecimal to a decimal manually, you must start by multiplying the hex number by 16. Then, you raise it to a power of 0 and increase that power by 1 each time according to the hexadecimal number equivalent.

We start from the right of the hexadecimal number and go to the left when applying the powers. Each time you multiply a number by 16, the power of 16 increases.

When converting a C9 hexadecimal to a decimal your work should look something like this:

Example :

9 = 9 * (16 ^ 0) = 9
C = 12 * (16 ^ 1) = 192

Then, we add the results.

192 + 9 = 201

Hexadecimal	1	2	3	4	5	6	7	8	9	A	B	C	D	E	F
Decimal	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15

Python Code

Run

def convert(hex):
    l = len(hex)
    decimal = 0
    pos = 0
    for i in range(l - 1, -1, -1):

        # if given index value is a digit (0 - 9)
        if '0' <= hex[i] <= '9':

            # if hex[i] is in range '0' - '9'
            # can convert string value to its integer value
            # by passing it to int() function
            digit = int(hex[i])
            decimal += digit * pow(16, pos)
            pos += 1

        # if given index is char in range [A, F]
        elif 'A' <= hex[i] <= 'F':

            # if hex[i] is in range 'A' - 'F'
            # can convert sting value to its int value
            # by subtracting 55(Refer Ascii table) as
            # ASCII val A: 65 and A must result 10 as value
            # to get ASCII value in Python can use ord() function
            digit = ord(hex[i]) - 55
            decimal += digit * pow(16, pos)
            pos += 1
    return decimal


hex = "C9"

print("decimal value of", hex, "is", convert(hex))

Output

Decimal value of C9 is 201

Program for octal to decimal conversion

Program for hexadecimal to decimal conversion

Program for decimal to binary conversion

Program for decimal to octal conversion

Program for decimal to hexadecimal conversion

Prime Course Trailer

Related Banners

Get PrepInsta Prime & get Access to all 200+ courses offered by PrepInsta in One Subscription

One comment on “Hexadecimal to Decimal Conversion in Python”

Arpita
hex_to_dec={‘0′:0,’1′:1,’2′:2,’3′:3,’4′:4,’5′:5,’6′:6,’7′:7,’8′:8,’9′:9,’A’:10,’B’:11,’C’:12,’D’:13,’E’:14,’F’:15}
n=input(‘Enter Hexadecimal Number:’).upper()
x=0
l=len(n)
for ch in n:
l=l-1
x=x+(hex_to_dec[ch]*(16**l))
print(‘Hexadecimal:’,n,’\ndecimal:’,x)

0

Log in to Reply