# Convert hexadecimal string to an integer number in C#

C# | Convert hexadecimal string to an integer: Here, we are going to learn how to convert a given string that contains a hexadecimal number in an integer number?
Submitted by IncludeHelp, on February 09, 2019

Given a hexadecimal string and we have to convert it into an integer number.

## Converting from hexadecimal string to integer

Let suppose you have a string "3039" which is a hexadecimal value of integer 12345, but this value is in string format, and you want to its integer (number) value.

To convert a hexadecimal string to an integer number – we use Convert.ToInt32() method.

Syntax:

```    Convert.ToInt32(input_string, Input_base);
```

Here,

• input_string is the input containing hexadecimal number in string format.
• input_base is the base of the input value – for a hexadecimal value it will be 16.

Example:

```    Input: "3039"
Function call:
Convert.ToInt32(input, 16);
Output:
12345

Input: "303a"
Function call:
Convert.ToInt32(input, 16);
Output:
12346

Input: "303ag" //not 'g' is not a valid hex digit
Function call:
Convert.ToInt32(input, 16);
Output:
Exception
```

Code:

```using System;
using System.Text;

namespace ConsoleApplication3
{
class Program
{
static void Main(string[] args)
{
//hex number as string
string input = "3039";
int output = 0;
//converting to integer
output = Convert.ToInt32(input, 16);
//printing the value
Console.WriteLine("Integer number: " + output);

//hit ENTER to exit
}
}
}
```

Output

```    Integer number: 12345
```

Example with Exception handling

Code:

```using System;
using System.Text;

namespace ConsoleApplication3
{
class Program
{
static void Main(string[] args)
{
string input = "";
int output = 0;
try
{
//input string

//converting to integer
output = Convert.ToInt32(input, 16);

Console.WriteLine("Integer number: " + output);
}
catch (Exception ex)
{
Console.WriteLine(ex.ToString());
}

//hit ENTER to exit
}
}
}
```

Output

```First run with valid input:
Integer number: 12345

Second run with valid input:
Integer number: 12346

Third run with invalid input:
System.FormatException: Additional non-parsable characters are at the end of the
string.
at System.ParseNumbers.StringToInt(String s, Int32 radix, Int32 flags, Int32*
currPos)
at System.Convert.ToInt32(String value, Int32 fromBase)
at ConsoleApplication3.Program.Main(String[] args) in F:\Ankur\SerialPort\Con
soleApplication3\ConsoleApplication3\Program.cs:line 19
```

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