Math

`Math.atan2`

Returns the angle in radians between the positive x-axis and the point (x, y)

Syntax

JavaScript

Math.atan2(y, x)

Parameters

Parameter	Type	Description
y	number	The y coordinate
x	number	The x coordinate

Return Value

The angle in radians (between -PI and PI)

Examples

Basic Usage

console.log(Math.atan2(1, 1)); // ~0.785 (PI/4)
console.log(Math.atan2(0, -1)); // ~3.14159 (PI)

Practical Example

function angleBetween(x1: number, y1: number, x2: number, y2: number) {
  return Math.atan2(y2 - y1, x2 - x1) * (180 / Math.PI);
}
console.log(angleBetween(0, 0, 1, 1)); // 45

Advanced Usage

const angles = [[0, 1], [1, 0], [0, -1], [-1, 0]];
angles.forEach(([y, x]) =>
  console.log(Math.atan2(y, x).toFixed(2))
);

Understanding Math.atan2

The Math.atan2 method in JavaScript returns the angle in radians between the positive x-axis and the point (x, y). It belongs to the Math object and is one of the most widely used methods for working with math values in modern JavaScript and TypeScript applications.

The method signature is Math.atan2(y, x). It accepts 2 parameters: y, x. When called, it returns the angle in radians (between -pi and pi). Understanding when and how to use atan2() helps you write more expressive, readable code.

Common use cases for Math.atan2 include data transformation, input validation, API response processing, and building reusable utility functions. It works well alongside related methods like math-sin, math-cos, math-tan, enabling you to chain operations together for complex data manipulation pipelines.

Browser support for Math.atan2 is excellent across all modern browsers including Chrome, Firefox, Safari, and Edge. It is also fully supported in Node.js and Deno. For older environments, transpilation with Babel or a polyfill may be needed.