Java Math Class

The Math class is Java's calculator, with things like rounding, powers, square roots and pi. It does the math that simple operators cannot.

In this page:

Basic Math Operations
Rounding Operations
Exponents and Roots
Trigonometry and Constants
Exact Arithmetic

Syntax

java

Math.function(number);  // e.g. Math.sqrt(x), Math.pow(x, y), Math.max(a, b)

Basic Math Operations

The Math class provides static methods for basic operations, like Math.abs() for absolute value and Math.max()/Math.min() for comparisons, without needing to instantiate anything.

Example: Basic Math Operations

java

// Define the class Main
public class Main {
	// Program entry point: the JVM starts running here
	public static void main(String[] args) {
		// Print a line to the console
		System.out.println(Math.abs(-5));
		// Print a line to the console
		System.out.println(Math.max(3, 7));
		System.out.println(Math.min(3, 7));
	}
}

Rounding Operations

Math.round(), Math.floor(), and Math.ceil() each round differently — nearest, down, and up respectively — and choosing the wrong one is a common source of off-by-one bugs in numeric code.

Example: Rounding Operations

java

public class Main {
	public static void main(String[] args) {
		System.out.println(Math.round(4.5)); // nearest
		System.out.println(Math.floor(4.9)); // down
		System.out.println(Math.ceil(4.1)); // up
	}
}

Exponents and Roots

Math.pow(base, exponent) computes exponents and Math.sqrt() computes square roots, both returning a double even when the inputs are integers.

Note that Math.pow is generally slower than direct multiplication for small fixed integer powers, so 'x * x' often beats Math.pow(x, 2).

Example: Exponents and Roots

java

// Define the class Main
public class Main {
	// Program entry point: the JVM starts running here
	public static void main(String[] args) {
		// Print a line to the console
		System.out.println(Math.pow(2, 3));
		// Print a line to the console
		System.out.println(Math.sqrt(16));
	}
}

Trigonometry and Constants

Math.sin(), Math.cos(), and constants like Math.PI support trigonometric and geometric calculations, all working in radians rather than degrees by default.

Converting between degrees and radians with Math.toRadians() and Math.toDegrees() is a common companion step when working with real-world angle values.

Example: Trigonometry and Constants

java

public class Main {
	public static void main(String[] args) {
		System.out.println(Math.PI);
		System.out.println(Math.sin(Math.PI / 2)); // radians, not degrees
	}
}

Exact Arithmetic

Methods like Math.addExact() throw an ArithmeticException on overflow instead of silently wrapping around, which is valuable when exact correctness matters more than raw speed.

Example: Exact Arithmetic

java

public class Main {
	public static void main(String[] args) {
		try {
			Math.addExact(Integer.MAX_VALUE, 1); // throws instead of silently wrapping
		} catch (ArithmeticException e) {
			System.out.println("Overflow detected: " + e.getMessage());
		}
	}
}

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Java Math Class

Basic Math Operations

Rounding Operations

Exponents and Roots

Trigonometry and Constants

Exact Arithmetic

Chapter Quiz — Complete all 10 topics to unlock

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