How to use the Excel ATAN function

The Excel ATAN function returns the inverse tangent or arc-tangent of a number. In geometric terms, the function returns the angle of a right-triangle given the ratio of its opposite side over its adjacent side. The ATAN function is the inverse of the TAN function

Syntax: =ATAN(number)

The ATAN function syntax has the following arguments:

• Number (Required): The tangent of the angle you want.

Example: Let’s look at some Excel ATAN function examples and explore how to use the ATAN function as a worksheet function in Microsoft Excel:

Syntax:  =ATAN(G26)

Result:

Based on the Excel spreadsheet above, the following ATAN examples would return: