Java Math round()

In this tutorial, we will learn about the Java Math.round() method with the help of examples.

The round() method rounds the specified value to the closest int or long value and returns it. That is, 3.87 is rounded to 4 and 3.24 is rounded to 3.

Example

class Main {
  public static void main(String[] args) {

    double a = 3.87;
    System.out.println(Math.round(a));

  }
}

// Output: 4

Syntax of Math.round()

The syntax of the round() method is:

Math.round(value)

Here, round() is a static method. Hence, we are accessing the method using the class name, Math.

round() Parameters

The round() method takes a single parameter.

value - number which is to be rounded

Note: The data type of the value should be either float or double.

round() Return Value

returns the int value if the argument is float
returns the long value if the argument is double

The round() method:

rounds upward if the value after the decimal is greater than or equal to 5
```
1.5 => 2
1.7 => 2
```
rounds downward if the value after the decimal is smaller than 5
```
1.3 => 1
```

Example 1: Java Math.round() with double

class Main {
  public static void main(String[] args) {

    // Math.round() method
    // value greater than 5 after decimal
    double a = 1.878;
    System.out.println(Math.round(a));  // 2


    // value equals to 5 after decimal
    double b = 1.5;
    System.out.println(Math.round(b));  // 2


    // value less than 5 after decimal
    double c = 1.34;
    System.out.println(Math.round(c));  // 1

  }
}

Example 2: Java Math.round() with float

class Main {
  public static void main(String[] args) {

    // Math.round() method
    // value greater than 5 after decimal
    float a = 3.78f;
    System.out.println(Math.round(a));  // 4


    // value equals to 5 after decimal
    float b = 3.5f;
    System.out.println(Math.round(b));  // 4


    // value less than 5 after decimal
    float c = 3.44f;
    System.out.println(Math.round(c));  // 3

  }
}

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