Exceljet

Quick, clean, and to the point

Excel ATAN2 Function

Excel ATAN2 function
Summary 
The Excel ATAN2 function returns the arctangent from x- and y-coordinates. In geometric terms, the function returns the radian angle corresponding to the input point.
Purpose 
Get arctangent from x- and y-coordinates
Return value 
The angle in radians of the point.
Syntax 
=ATAN2 (x_num, y_num)
Arguments 
  • x_num - The x coordinate of the input point.
  • y_num - The y coordinate of the input point.
Version 
Usage notes 

The Excel ATAN2 function returns the arctangent from the x and y coordinates of a point. In geometric terms, the function returns the radian angle corresponding to the coordinates of the input point. If you imagine a ray starting from the origin of the coordinate system and extending outwards, every point along the ray will return the same angle value. A circle of radius one demonstrates all possible return values for the function.

ATAN2 Function Unit Circle

For negative y-values the function returns a negative angle. An angle is measured from the positive x-axis direction with the positive direction in the counter-clockwise direction and the negative direction in the clockwise direction.

ATAN2 Negative Y Value

Convert Output to Degrees

To convert the output of the ATAN2 function from radians to degrees the formula is:

=ATAN2(x,y)*180/PI() // Returns angle in degrees

Alternatively, the degrees formula can be used to convert the angle to degrees.

=DEGREES(ATAN2(x,y))// Returns angle in degrees

Difference Between ATAN and ATAN2

For points in the first and fourth quadrant, the ATAN2 function returns identical output to the ATAN function. This relationship is expressed in the formula below:

= ATAN2(x,y) = ATAN(y/x)

For points in the second and third quadrant, the ATAN function returns the angle relative to the negative x-direction axis.

ATAN2 vs ATAN

 

Download 200+ Excel Shortcuts

Get over 200 Excel shortcuts for Windows and Mac in one handy PDF.