TAN Excel function is an inbuilt trigonometric function in excel which is used to calculate the cosine value of given number or in terms of trigonometry the cosine value of a given angle, here the angle is a number in excel and this function takes only a single argument which is the input number provided.

**Syntax**: =TAN (number)

The TAN function syntax has the following arguments:

**Number**Required. The angle in radians for which you want the tangent.

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

Suppose we have 10 right-angled triangles, given with their angles and length on one side and we need to calculate the length of the other side.

In Excel, the length of the adjacent side (base), will be calculated by the TAN formula

Applying the TAN formula for 10 triangles we can get the length of the adjacent side of the triangle

**Syntax**: **=F2/(TAN(RADIANS(C2)))**

**Result**:

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

**Syntax**: =F3/(TAN(RADIANS(C3)))**Result**: 0.776457135

**Syntax**: =F4/(TAN(RADIANS(C4)))**Result**: 2.5

**Syntax**: =F5/(TAN(RADIANS(C5)))**Result**: 4.242640687

**Syntax**: =F6/(TAN(RADIANS(C6)))**Result**: 4.330127019

**Syntax**: =F7/(TAN(C7*PI()/180))**Result**: 2.047880111

**Syntax**: =F8/(TAN(C8*PI()/180))**Result**: 7.660444431

**Syntax**: =F9/(TAN(C9*PI()/180))**Result**: 7.713451316

**Syntax**: =F10/(TAN(C10*PI()/180))**Result**: 2.736161147

**Syntax**: =F11/(TAN(C11*PI()/180))**Result**: 1.690473047

**Note**:

- If the angle is given in degrees for which we have to calculate TAN then firstly we have to calculate RADIANS for the same by using formula =RADIAN(degree) or we can multiply the angle by PI()/180.
- The TAN function always uses the parameter as RADIANS.
- If the TAN function has #VALUE! An error then it means that text is used in the place of a number.
- If the cell chooses as a blank cell in the place of a number then the result would be 1 because the tangent is 1 for the radiant 0. So, always be careful while selecting a cell.