How to convert hex string into int in Python?

A Hexadecimal is the base-16 number system that uses the digits from '0 to 9' and letters from 'A to F'. It is commonly used in computers to represent binary data in a readable format.

In this article, we will learn about converting hex strings into integers. For example, if we receive input as a hex string ("fe00") and need to convert it into an integer, Python provides multiple methods. Let's explore them one by one.

Using int() Function

The int() function is the most common method to convert a hex string to an integer. It accepts a base parameter to specify the number system.

Syntax

int(value, base)

Example

Let's convert a hex string to an integer using the int() function ?

hex_str = "fe00"
print("The given hex string is:", hex_str)

result = int(hex_str, 16)
print("The resultant integer is:", result)

The given hex string is: fe00
The resultant integer is: 65024

Using literal_eval() Method

The literal_eval() method from the ast module evaluates a string containing a valid Python literal expression. For hex conversion, the string must include the '0x' prefix.

Syntax

ast.literal_eval(expression)

Example

Convert '0xfe00' to an integer using literal_eval() method ?

import ast

hex_str = "0xfe00"
print("The given hex string is:", hex_str)

result = ast.literal_eval(hex_str)
print("The resultant integer is:", result)

The given hex string is: 0xfe00
The resultant integer is: 65024

Using struct.unpack() Method

The struct module works with binary data and can convert hex strings to integers. First, convert the hex string to bytes, then unpack it using a format specifier.

Syntax

struct.unpack(format, buffer)

Example

Convert '1A2D' to an integer using struct.unpack() method ?

import struct

hex_str = "1A2D"
print("The given hex string is:", hex_str)

# Convert hex string to bytes
hex_bytes = bytes.fromhex(hex_str)
# Unpack as unsigned short (2 bytes, big-endian)
result = struct.unpack(">H", hex_bytes)[0]
print("The resultant integer is:", result)

The given hex string is: 1A2D
The resultant integer is: 6701

Comparison

Conclusion

Use int(hex_string, 16) for simple hex to integer conversion. Use literal_eval() for safe evaluation when the string includes '0x' prefix. Use struct.unpack() when working with binary data formats.