Java How to Convert Char to Int with Examples

In Java, convert a char to int by casting like int num = (int) ch; or by using Character.getNumericValue(ch); to get the numeric value.

Examples

Input'5'

Output53

Input'A'

Output65

Input'9'

Output57

How to Think About It

To convert a character to an integer in Java, you can either get its ASCII code by casting it to int or get its numeric digit value if it represents a number. Casting gives the Unicode number, while using Character.getNumericValue() returns the actual digit value for number characters.

Algorithm

1

Take the input character.

2

If you want the ASCII/Unicode code, cast the character to int.

3

If you want the numeric digit value, use Character.getNumericValue() method.

4

Return the resulting integer.

Code

java

public class CharToInt {
    public static void main(String[] args) {
        char ch = '5';
        int asciiValue = (int) ch;
        int numericValue = Character.getNumericValue(ch);
        System.out.println("ASCII value: " + asciiValue);
        System.out.println("Numeric value: " + numericValue);
    }
}

Output

ASCII value: 53
Numeric value: 5

Dry Run

Let's trace converting char '5' to int using casting and getNumericValue.

1

Cast char to int

char ch = '5'; int asciiValue = (int) ch; // asciiValue = 53

2

Use getNumericValue

int numericValue = Character.getNumericValue(ch); // numericValue = 5

Operation	Result
(int) '5'	53
Character.getNumericValue('5')	5

Why This Works

Step 1: Casting char to int

Casting a char to int returns its Unicode (ASCII) numeric code.

Step 2: Using Character.getNumericValue

This method converts a digit character to its actual integer value, e.g., '5' to 5.

Alternative Approaches

Subtract '0' from char

java

public class CharToIntAlt {
    public static void main(String[] args) {
        char ch = '7';
        int num = ch - '0';
        System.out.println(num);
    }
}

This works only if the char is a digit ('0' to '9'). It is fast and simple.

Complexity: O(1) time, O(1) space

Time Complexity

Conversion is a simple arithmetic or method call, so it runs in constant time.

Space Complexity

No extra memory is needed besides the integer variable to store the result.

Which Approach is Fastest?

Subtracting '0' is fastest but only works for digit chars; casting and getNumericValue are more general.

Approach	Time	Space	Best For
Casting (int) ch	O(1)	O(1)	Getting ASCII/Unicode code
Character.getNumericValue(ch)	O(1)	O(1)	Getting digit value for any numeric char
Subtract '0' from char	O(1)	O(1)	Fast digit char to int conversion