# Math.atan2()

The `Math.atan2()` function returns the arctangent of the quotient of its arguments.

## Syntax

JavaScript
`Math.atan2(<var>y</var>, <var>x</var>)`

`y`
First number.
`x`
Second number.

### Return value

The arctangent of the quotient of the given arguments.

## Description

The `Math.atan2()` method returns a numeric value between -π and π representing the angle theta of an `(x, y)` point. This is the counterclockwise angle, measured in radians, between the positive X axis, and the point `(x, y)`. Note that the arguments to this function pass the y-coordinate first and the x-coordinate second. `Math.atan2()` is passed separate `x` and `y` arguments, and `Math.atan()` is passed the ratio of those two arguments.

Because `atan2()` is a static method of `Math`, you always use it as `Math.atan2()`, rather than as a method of a `Math` object you created (`Math` is not a constructor).

## Examples

### Using `Math.atan2()`

JavaScript
```Math.atan2(90, 15); // 1.4056476493802699
Math.atan2(15, 90); // 0.16514867741462683

Math.atan2(±0, -0);               // ±PI.
Math.atan2(±0, +0);               // ±0.
Math.atan2(±0, -x);               // ±PI for x > 0.
Math.atan2(±0, x);                // ±0 for x > 0.
Math.atan2(-y, ±0);               // -PI/2 for y > 0.
Math.atan2(y, ±0);                // PI/2 for y > 0.
Math.atan2(±y, -Infinity);        // ±PI for finite y > 0.
Math.atan2(±y, +Infinity);        // ±0 for finite y > 0.
Math.atan2(±Infinity, x);         // ±PI/2 for finite x.
Math.atan2(±Infinity, -Infinity); // ±3*PI/4.
Math.atan2(±Infinity, +Infinity); // ±PI/4.```

## Specifications

Specification Status Comment
ECMAScript 1st Edition (ECMA-262) Standard Initial definition. Implemented in JavaScript 1.0.
ECMAScript 5.1 (ECMA-262)
The definition of 'Math.atan2' in that specification.
Standard
ECMAScript 2015 (6th Edition, ECMA-262)
The definition of 'Math.atan2' in that specification.
Standard
ECMAScript 2017 Draft (ECMA-262)
The definition of 'Math.atan2' in that specification.
Draft

## Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support (Yes) (Yes) (Yes) (Yes) (Yes)
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support (Yes) (Yes) (Yes) (Yes) (Yes) (Yes)