Java ceil() method with Examples

Last Updated : 21 Jan, 2026

The Math.ceil() method in Java is used to return the smallest integer value that is greater than or equal to a given number. The returned value is of type double and represents the mathematical ceiling of the argument. This method belongs to the java.lang.Math class.

Java 
class GFG {
    public static void main(String[] args) {
        double num = 2.3;
        System.out.println(Math.ceil(num));
    }
}

Output
3.0

Explanation:

  • A decimal value 2.3 is stored in the variable num.
  • The Math.ceil() method is called with num as the argument.
  • The method rounds the value up to the nearest integer.
  • The result is returned as a double value (3.0).

Syntax: 

public static double ceil(double a) 

  • Parameter: "a" the double value whose ceiling is to be determined.
  • Return Value: Returns the nearest integer value (as double) that is greater than or equal to the given argument.

Special Cases

  • If the argument is already an integer, the same value is returned.
  • If the argument is NaN, positive infinity, negative infinity, positive zero, or negative zero, the result is the same as the argument.
  • If the argument is less than 0 but greater than -1.0, the result is negative zero (-0.0).

Example 1: This program demonstrates how the Math.ceil() method works with different types of double values in Java.

java 
import java.lang.Math;
class GFG {
    public static void main(String args[]) {
        double a = 4.3;
        double b = 1.0 / 0;
        double c = 0.0;
        double d = -0.0;
        double e = -0.12;
        System.out.println(Math.ceil(a));
        System.out.println(Math.ceil(b));
        System.out.println(Math.ceil(c));
        System.out.println(Math.ceil(d));
        System.out.println(Math.ceil(e));
    }
}

Output
5.0
Infinity
0.0
-0.0
-0.0

Explanation:

  • The Math class is used to access the ceil() method.
  • Variable a holds a positive decimal value, which is rounded up to the next integer.
  • Variable b represents positive infinity, so the result remains infinity.
  • Variable c is positive zero, and the output remains 0.0.
  • Variable d is negative zero, and the output remains -0.0.
  • Variable e is a negative value between -1.0 and 0.0, so the result is -0.0.
  • Each result is printed to show how Math.ceil() behaves in different cases.

Example 2: This program shows how the Math.ceil() method rounds a decimal number up to the nearest integer value.

Java 
class GFG {
    public static void main(String[] args) {
        double number = 3.5;
        double result = Math.ceil(number);
        System.out.println(result);
    }
}

Output :

4.0

Explanation:

  • A decimal value 3.5 is stored in the variable number.
  • The Math.ceil() method is called with number as the argument.
  • The method rounds the value upward to the nearest integer.
  • The result is returned as a double (4.0).
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