JavaScript Math

JavaScript Math Object

The built-in Math object in JavaScript provides properties and methods for performing mathematical operations. It is not a constructor, so you don’t create instances of Math. All its properties and methods are static and accessed directly via Math.

Common Math Properties (Constants)

JavaScript provides several built-in mathematical constants:

console.log(Math.PI);       // Output: 3.141592653589793 (PI)
console.log(Math.E);        // Output: 2.718281828459045 (Euler's number)
console.log(Math.SQRT2);    // Output: 1.4142135623730951 (Square root of 2)
console.log(Math.SQRT1_2);  // Output: 0.7071067811865476 (Square root of 1/2)
console.log(Math.LN2);      // Output: 0.6931471805599453 (Natural logarithm of 2)
console.log(Math.LN10);     // Output: 2.302585092994046 (Natural logarithm of 10)
console.log(Math.LOG2E);    // Output: 1.4426950408889634 (Base 2 logarithm of E)
console.log(Math.LOG10E);   // Output: 0.4342944819032518 (Base 10 logarithm of E)

Numeric Operations

Math.min() and Math.max(): Find the lowest or highest value in a list of arguments.

console.log(Math.min(0, 150, 30, 20, -8, -200)); // Output: -200
console.log(Math.max(0, 150, 30, 20, -8, -200)); // Output: 150

// To find min/max in an array, use the spread operator:
const numbers = [10, 5, 100, 2, 25];
console.log(Math.min(...numbers)); // Output: 2
console.log(Math.max(...numbers)); // Output: 100

Math.abs(x): Returns the absolute (positive) value of x.

console.log(Math.abs(-7.25)); // Output: 7.25

Math.pow(x, y): Returns the value of x to the power of y (x^y).

console.log(Math.pow(2, 3)); // Output: 8 (2 * 2 * 2)
console.log(Math.pow(4, 0.5)); // Output: 2 (Square root of 4)

Math.sqrt(x): Returns the square root of x.

console.log(Math.sqrt(9)); // Output: 3

Math.cbrt(x): Returns the cube root of x (ES6+).

console.log(Math.cbrt(27)); // Output: 3

Math.sign(x): Returns the sign of a number, indicating whether x is positive, negative or zero (ES6+). (1 for positive, -1 for negative, 0 for zero)

console.log(Math.sign(10));   // Output: 1
console.log(Math.sign(-5));   // Output: -1
console.log(Math.sign(0));    // Output: 0

Rounding Methods

Math.round(x): Rounds x to the nearest integer.

console.log(Math.round(4.7)); // Output: 5
console.log(Math.round(4.4)); // Output: 4
console.log(Math.round(4.5)); // Output: 5 (rounds .5 up)

Math.ceil(x): Rounds x up to the nearest integer.

console.log(Math.ceil(4.4));  // Output: 5
console.log(Math.ceil(4.0));  // Output: 4

Math.floor(x): Rounds x down to the nearest integer.

console.log(Math.floor(4.7)); // Output: 4
console.log(Math.floor(4.0)); // Output: 4

Math.trunc(x): Returns the integer part of x by removing any fractional digits (ES6+).

console.log(Math.trunc(4.7));  // Output: 4
console.log(Math.trunc(-4.2)); // Output: -4

Random Numbers

Math.random(): Returns a pseudo-random floating-point number between 0 (inclusive) and 1 (exclusive).

console.log(Math.random()); // e.g., 0.123456789

// To get a random integer between min (inclusive) and max (inclusive):
function getRandomInt(min, max) {
  min = Math.ceil(min);
  max = Math.floor(max);
  return Math.floor(Math.random() * (max - min + 1)) + min;
}
console.log(getRandomInt(1, 10)); // Random integer between 1 and 10

Trigonometric and Logarithmic Functions

The Math object also includes standard trigonometric functions (like Math.sin(), Math.cos(), Math.tan(), Math.asin(), Math.acos(), Math.atan(), Math.atan2()) and logarithmic functions (Math.log() (natural log), Math.log10() (base 10 log, ES6+), Math.log2() (base 2 log, ES6+), Math.exp() (E^x)).

Arguments for trigonometric functions are typically in radians.

console.log(Math.sin(Math.PI / 2)); // Output: 1 (sin(90 degrees))
console.log(Math.log(Math.E));      // Output: 1 (ln(e))
console.log(Math.log10(100));     // Output: 2 (log base 10 of 100)

Math Object Methods Overview

Complete Math Reference

For a comprehensive reference, including detailed descriptions and examples of all Math properties and methods, consult the MDN Web Docs for the JavaScript Math object.