What Is a Double Data Type in Java?


Scott Campbell

What Is a Double Data Type in Java?

In Java, a double is a data type that represents a double-precision 64-bit floating-point number. It is used to store decimal numbers with greater precision than the float data type.


The syntax for declaring a variable of type double is:

  • double variableName;
  • double variableName = initialValue;

Precision and Range

The double data type provides more precision than the float data type. It can store numbers with up to 15 decimal digits of precision. The range of values that can be represented by a double is approximately ±1.7 x 10-308 to ±1.7 x 10+308.

Example Usage:

// Declaring a double variable without initializing it
double pi;

// Initializing a double variable
double radius = 5.5;

// Performing calculations using double variables
double circumference = 2 * Math.PI * radius;
double area = Math.PI * radius * radius;

// Printing the results
System.out.println("Circumference: " + circumference);
System.println("Area: " + area); 


  • The “Math.PI” in the example above is a constant value representing the mathematical constant π (pi).
  • The “System.println()” statement is used to display the results on the console.


The double data type in Java is essential for handling decimal numbers with high precision. It allows programmers to perform calculations that require more accuracy than what can be achieved with the float data type. Understanding and utilizing the double data type effectively can greatly enhance the functionality and reliability of your Java programs.

If you found this tutorial helpful, feel free to explore other tutorials on our website to further expand your knowledge of Java programming!

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