Article updated on March 27, 2018

The ATAN2 function calculates the arctangent of an angle using specific x- and y-coordinates. The returned angle is in radians between -pi to pi, including pi.

The angle is between the x-axis and the line from (0,0) and point (x_num, y_num)


Excel Function Syntax

ATAN2(x_num, y_num)


x_num Required. The x-coordinate.
y_num Required. The y-coordinate.


If x_num is 1 and y_num is 1 then the angle between the x-axis and the line from (0,0) to (1,1) is 45 degrees or 1/4 pi radians. 1/4 pi is 0.785398163.