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JavaScript atan2() Method

< JavaScript Math Object

Example - atan2(y,x)

Assume you had a point with the (x,y) coordinates of (4,8), you could calculate the angle in radians between that point and the positive X axis as follows:

Math.atan2(8, 4);

The output of the code above will be:

1.1071487177940904

Try it Yourself »

Definition and Usage

The atan2() method returns the arctangent of the quotient of its arguments, as a numeric value between PI and -PI radians.

The number returned represents the counterclockwise angle in radians (not degrees) between the positive X axis and the point (x, y).

Note: With atan2(), the y coordinate is passed as the first argument and the x coordinate is passed as the second argument.

Browser Support

Method
atan2()	Yes	Yes	Yes	Yes	Yes

Syntax

Math.atan2(y,x)

Parameter	Description
y	Required. A number representing the y coordinate
x	Required. A number representing the x coordinate

Technical Details

Return Value:	A Number, from PI to -PI, or NaN if the value(s) are empty
JavaScript Version:	1.0

< JavaScript Math Object