# How to Use TAN Function

The tangent of an angle is the ratio of the length of the opposite side to the length of the adjacent side.

In excel, TAN function returns the tangent of the given angle in radians.

Formula:

=TAN(number)

Explanations:

Number is required, the angle in radian that you want the tangent value.

Cautions:

The number (angle) needs to be in radians. When the angle is in degrees, using the angle multiply PI()/180 to convert the angle to radians first.

Download: TAN Function