# WorksheetFunction.Atan2 Method (Excel)

Office 2013

Published: July 16, 2012

Returns the arctangent, or inverse tangent, of the specified x- and y-coordinates. The arctangent is the angle from the x-axis to a line containing the origin (0, 0) and a point with coordinates (x_num, y_num). The angle is given in radians between -pi and pi, excluding -pi.

## Syntax

expression .Atan2(Arg1, Arg2)

expression A variable that represents a WorksheetFunction object.

### Parameters

Name

Required/Optional

Data Type

Description

Arg1

Required

Double

The x-coordinate of the point.

Arg2

Required

Double

The y-coordinate of the point.

Double

## Remarks

• A positive result represents a counterclockwise angle from the x-axis; a negative result represents a clockwise angle.

• The following conditions apply:

• Where x > 0 ATAN2(x,y) = ATAN(y/x)

• Where y >= 0, x < 0 ATAN2(x,y) = ATAN(y/x)+PI()

• Where y < 0, x < 0 ATAN2(x,y) = ATAN(y/x) - PI()

• Where y > 0, x = 0 ATAN2(x,y) = PI()/2

• Where y < 0, x = 0 ATAN2(x,y) = -PI()/2

• If both x and y are 0, Atan2 returns an error value.

• To express the arctangent in degrees, multiply the result by 180/PI( ) or use the Degrees method.