Java.lang.Math.round() Method


The java.lang.Math.round(double a) returns the closest long to the argument. The result is rounded to an integer by adding 1/2, taking the floor of the result, and casting the result to type long. Special cases −

  • If the argument is NaN, the result is 0.

  • If the argument is negative infinity or any value less than or equal to the value of Long.MIN_VALUE, the result is equal to the value of Long.MIN_VALUE.

  • If the argument is positive infinity or any value greater than or equal to the value of Long.MAX_VALUE, the result is equal to the value of Long.MAX_VALUE.


Following is the declaration for java.lang.Math.round() method

public static long round(double a)


a − a floating-point value to be rounded to a long.

Return Value

This method returns the value of the argument rounded to the nearest long value.




The following example shows the usage of lang.Math.round() method.

package com.tutorialspoint;

import java.lang.*;

public class MathDemo {

   public static void main(String[] args) {

      // get two double numbers
      double x = 1654.9874;
      double y = -9765.134;
      // find the closest long for these doubles
      System.out.println("Math.round(" + x + ")=" + Math.round(x));
      System.out.println("Math.round(" + y + ")=" + Math.round(y));

Let us compile and run the above program, this will produce the following result −