The Excel TAN Function

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Tangent of an Angle

For the simple right-angled triangle below, the tangent of the angle θ, is the ratio of the opposite side, o, to the adjacent side, a.

i.e. for the triangle above,

The trig. ratios are discussed further on the Wikipedia Trigonometric Ratios Page

Related Functions :

COS Function

SIN Function

Basic Description

The Excel TAN function calculates the tangent of a given angle (which is supplied in radians).

The format of the function is :

TAN( Number )

Where the Number argument is the angle, in radians, that you want to calculate the tangent of.

Converting from Degrees to Radians

If your angle is in degrees, you will need to convert it into radians before supplying it to the tan function.

The easiest way to do this is to use the Excel Radians function:

=RADIANS( Degrees )

Examples of this are given below.

Example

Column B of the spreadsheet below, shows examples of the Excel Tan Function, used to calculate the tangent of different angles, which are in either degrees or radians.

The formulas are shown in the spreadsheet on the left and the results are shown in the spreadsheet on the right.

Formulas