## How to convert a decimal value to hexadecimal in Python:

In this post, we will learn different ways to convert a *decimal* value to *hexadecimal* using Python. *Decimal* number system is base *10* number system. We can use *0* to *9* to represent a decimal number. *Hexadecimal* number system is base *16* number system. We have to use *0* to *9* in hexadecimal to represent *0* to *9* decimal values and *A* to *F* in hexadecimal for *10* to *15* decimal values.

We can write our own function or we can use an inbuilt function *hex* to do the *decimal to hexadecimal* conversion.

Before we write our program, let’s understand the algorithm to do the conversion.

### Algorithm to convert a decimal to hexadecimal:

Let’s learn the algorithm to convert a *decimal* value to *hexadecimal*:

- Read the decimal value from the user.
- Divide the decimal number by
*16*. - Store the remainder in
*hexadecimal*. - Keep the result and keep dividing the decimal by
*16*until you get*0*. - If you combine the remainders in reverse, it will be the
*hexadecimal*conversion.

### Example to convert decimal to hexadecimal:

Let me show you an example.

The following table shows the *decimal* and *hexadecimal* conversion of the digits:

Decimal | Hexadecimal |
---|---|

0 | 0 |

1 | 1 |

2 | 2 |

3 | 3 |

4 | 4 |

5 | 5 |

6 | 6 |

7 | 7 |

8 | 8 |

9 | 9 |

10 | A |

11 | B |

12 | C |

13 | D |

14 | E |

15 | F |

Now, let’s convert *761* to *hexadecimal*:

*761/16*, the quotient is*47*and remainder is*9*.*9*is*9*in*hexadecimal**47/16*, the quotient is*2*and remainder is*15*.*15*is*F*in*hexadecimal**2/16*, the quotient is*0*and the remainder is*2*.*2*is*2*in*hexadecimal*

If we combine the remainders in reverse, it is *2F9*. So, the hexadecimal representation of *761* is *2F9*.

### Python program 1: Convert decimal to hexadecimal by dividing the number repeatedly:

Let’s write it down in code. This program will take one number as input from the user and it will keep dividing the number by *16* until the quotient becomes *0*.

It follows the same steps as we have discussed above.

```
hex_dict = {0: '0',
1: '1',
2: '2',
3: '3',
4: '4',
5: '5',
6: '6',
7: '7',
8: '8',
9: '9',
10: 'A',
11: 'B',
12: 'C',
13: 'D',
14: 'E',
15: 'F'}
num = int(input('Enter a number: '))
hex = ''
while(num > 0):
remainder = num % 16
hex = hex_dict[remainder] + hex
num = num // 16
print(f'Hexadecimal: {hex}')
```

Here,

*hex_dict*is a dictionary with*decimal*keys and*hexadecimal*values. We will use this dictionary to get the hexadecimal value for the remainders.- It asks the user to enter a number and stores it in the
*num*variable. *hex*is an empty string variable to hold the hexadecimal string.- The
*while loop*is finding the hexadecimal value. It keeps running and finds the*remainder*by dividing the number by*16*. It picks the hexadecimal value from the dictionary and appends it to the start of*hex*. - Once the loop ends, it prints the hexadecimal value.

If you run this program, it will print output as like below:

```
Enter a number: 761
Hexadecimal: 2F9
```

### Python program 2: Convert decimal to hexadecimal by using a separate method:

Let’s use a separate method to do the conversion.

```
def decimal_to_hex(num):
hex_dict = {0: '0',
1: '1',
2: '2',
3: '3',
4: '4',
5: '5',
6: '6',
7: '7',
8: '8',
9: '9',
10: 'A',
11: 'B',
12: 'C',
13: 'D',
14: 'E',
15: 'F'}
hex = ''
while(num > 0):
remainder = num % 16
hex = hex_dict[remainder] + hex
num = num // 16
return hex
num = int(input('Enter a number: '))
print(f'Hexadecimal: {decimal_to_hex(num)}')
```

We created a method *decimal_to_hex* that takes a number as the parameter and returns the hexadecimal value. This is exactly the same program we discussed above. The only difference is that we are using a new method to do the calculation.

It will print a similar result.

```
Enter a number: 1023
Hexadecimal: 3FF
```

### Python program 3: Convert decimal to hexadecimal by using a recursive method:

We can use a *recursive* method to convert a decimal to hexadecimal. Let’s take a look at the program:

```
hex_dict = {0: '0',
1: '1',
2: '2',
3: '3',
4: '4',
5: '5',
6: '6',
7: '7',
8: '8',
9: '9',
10: 'A',
11: 'B',
12: 'C',
13: 'D',
14: 'E',
15: 'F'}
def decimal_to_hex(num, hex):
if num == 0:
return hex
remainder = num % 16
return decimal_to_hex(num // 16, hex_dict[remainder] + hex)
num = int(input('Enter a number: '))
print(f'Hexadecimal: {decimal_to_hex(num, "")}')
```

Here,

*decimal_to_hex*is a recursive method. It takes a number and one string as the parameter.- If the value of the number is
*0*, it will return the string. - Else, it finds the
*remainder*and calls*decimal_to_hex*again to find the hexadecimal value. It passes*num // 16*as the number and appends the hexadecimal value to the front of the hex string as the second parameter.

If you run this program, it will print a similar result.

```
Enter a number: 1023
Hexadecimal: 3FF
```

### Python program 4: Decimal to hexadecimal by using hex:

*hex()* is a built-in method that can be used to convert an integer to hexadecimal. This method takes an integer as the parameter and returns the *hexadecimal* value.

`hex(num)`

Where *num* is the number parameter. It returns the hexadecimal string. It throws *TypeError* if anything other than integer values are passed to *hex*.

```
num = int(input('Enter a number: '))
print(f'Hexadecimal: {hex(num)}')
```

It will give output as like below:

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