Convert float to double in Java

Tags: double float Convert

In this Java core tutorial, we learn how to convert float value into double value in Java via different solutions.

Assign float variable to double variable

In Java, to convert a float value to double value we can easily assign float variable to double variable as following Java program.

ConvertFloatToDoubleExample1.java 

public class ConvertFloatToDoubleExample1 {
    public static void main(String[] args) {
        float value1 = 9.8F;
        double value2 = value1;

        System.out.println("float value: " + value1);
        System.out.println("double value: " + value2);
    }
}
The output is: 
float value: 9.8
double value: 9.800000190734863

Using Double.valueOf() method to instantiate Double from float value

We can use the Double.valueOf() method to initialize a double value from a given float value as Java code below.

ConvertFloatToDoubleExample2.java 

public class ConvertFloatToDoubleExample2 {
    public static void main(String[] args) {
        float value1 = 20.09F;
        double value2 = Double.valueOf(value1);

        System.out.println("float value: " + value1);
        System.out.println("double value: " + value2);
    }
}
The output is: 
float value: 20.09
double value: 20.09000015258789

Using Float.doubleValue() method to get double value of a Float object

With a Float object in Java we can use Float.doubleValue() method to return double value of it.

ConvertFloatToDoubleExample3.java 

public class ConvertFloatToDoubleExample3 {
    public static void main(String[] args) {
        Float value1 = Float.valueOf(20.05F);
        double value2 = value1.doubleValue();

        System.out.println("float value: " + value1);
        System.out.println("double value: " + value2);
    }
}
The output is: 
float value: 20.05
double value: 20.049999237060547

Happy Coding 😊

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