How To Convert double To int In Java?

In this article, we will see, how to convert a double value to an integer value in Java programming language.

Let’s say, you have a double primitive value (ex 82.14), but you need an int value (ex. 82) for further operations. So, let’s see how to convert double to int in Java.

There are three ways you can convert double to int. I have listed the three ways below.

1. convert double to int - using typecasting
2. convert double to int - using Math.round()
3. convert double to int - using Double.IntValue()

Let’s see these ways one by one.

You may like to visit: How To Convert An Integer To String In Java

1. Convert double to int - using typecasting

We know double is a 64-bit primitive value, and int is a 32-bit primitive value. So, to convert double to int, we can downcast the double value to int.

I have given a simple example below that shows how to convert double to int using typecasting.

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/**
 * A Java program to convert double to int using typecasting 
 * @author Gaurav Kukade at coderolls.com
 **/
public class DoubleToIntUsingTypecasting{

  public static void main(String []args){
    double doubleValue = 82.14; // 82.14
    
    System.out.println("doubleValue: "+doubleValue);
    
    //typecase double to int
    int intValue = (int) doubleValue; // 82
    
    System.out.println("intValue: "+intValue);
  }
}

Output:

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doubleValue: 82.14
intValue: 82

The problem with the typecasting is that it will truncate the value after the decimal point. It will not round it.

In the case of 82.14, we will get an int value of 82, which looks ok. But when we have a double value like 82.99, we will get only 82 and loss the 0.99 that is ~1.

It may create an issue in your calculations.

In the case of 82.99, it should be rounded to 83 and then converted to int.

It is not possible with typecasting, but our next solution can achieve it.

2. convert double to int - using Math.round()

Math.round() method will round the floating-point value to the nearest long value. Then we can typecast it to the int.

I have given a simple Java program below that shows how to convert double to int using the Math.round() method.

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/** 
 * A Java program to convert double to int using 
 * Math.round() method 
 * @author coderolls.com
 **/
public class DoubleToIntUsingRoundMethod{

  public static void main(String []args){
    // case 1
    double doubleValue = 82.14; // 82.14
    
    System.out.println("doubleValue: "+doubleValue);
    
    //typecase double to int
    int intValue = (int) Math.round(doubleValue); // 82
    
    System.out.println("intValue: "+intValue);
    
    System.out.println();
    
    // case 2
    double nextDoubleValue = 82.99; // 
    
    System.out.println("nextDoubleValue: "+nextDoubleValue);
    
    // Math.round(nextDoubleValue) returns long value
    //typecase long to int
    int nextIntValue = (int) Math.round(nextDoubleValue); // 83
    
    System.out.println("nextIntValue: "+nextIntValue);              
  }
}

Output:

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doubleValue: 82.14
intValue: 82

nextDoubleValue: 82.99
nextIntValue: 83

3. convert double to int - using Double.IntValue()

In this way, we will convert the double primitive value to the Double wrapper class, and then we can use the intValue() method of the Double wrapper class.

This method does not round the value before converting it to the int value. It will remove the digits after the decimal point.

I have given a simple java program below that shows how to convert double to int using the Double.IntValue() method.

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/**
 * 
 * A Java program to convert double to int using 
 * Double.intValue() method  
 * @author coderolls.com
 * 
 **/
public class DoubleToIntUsingIntValueMethod{

  public static void main(String []args){
    double doubleValue = 82.14; // 82.14
    
    System.out.println("doubleValue: "+doubleValue);
    
    //create a Double wrapper object
    Double doubleValueObject = new Double(doubleValue);
    
    
    //typecase double to int
    int intValue = doubleValueObject.intValue(); // 82
    
    System.out.println("intValue: "+intValue);
  }
}

Output:

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doubleValue: 82.14
intValue: 82

Conclusion

We can convert double to int in java using the three ways given below.

1. convert double to int - using typecasting

In this method we typecast the double value to int as given below,

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int intValue = (int) doubleValue;

But in this way, we will lose the value after the decimal point. It will not do the rounding before converting double to int.

**2. convert double to int - using Math.round() **

In this way, we use the Math.round() method for the rounding purpose.

Math.round() method round the double value to the nearest long, and then we can typecast long to the int as given below.

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int nextIntValue = (int) Math.round(nextDoubleValue);

3. convert double to int - using Double.IntValue()

In this way, we convert the double value to the Double wrapper class, and then we use the Double.IntValue() method to get the int value.

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//create a Double wrapper object
Double doubleValueObject = new Double(doubleValue);
        
//typecase double to int
int intValue = doubleValueObject.intValue(); 

In this way we will lose the digits after the decimal points.

So this is how we convert a double to int in Java. You can check all three (DoubleToIntUsingTypecasting.java, DoubleToIntUsingRoundMethod.java, DoubleToIntUsingIntValueMethod.java) programs on GitHub

You can read more about string to int and int to string conversion.

You can visit my YouTube channel ‘coderolls’ to find more video tutorials.