The PI Function in Excel returns the mathematical constant “pi.” To recap, PI is the ratio of a circle’s circumference and its diameter. Often, we would use the PI Function in Excel, especially when our business is required to do geometric calculations. These calculations entail calculating the area of a new office space, a new factory, etc.

When a human does a PI calculation, it will approximate PI as 3.14. However, Excel stores the value of PI accurately to 15 digits and up to 14 decimal places.

**Syntax**: = PI ()

The PI function syntax has the following arguments:

- There are no parameters or arguments for the PI function. The PI function returns pi which is a value of 3.14159265358979

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

**Example 1**:

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

**Syntax**: =COS(PI()/4)**Result**: 0.707106781

**Syntax**: =SIN(PI()/2)**Result**: 1

**Syntax**: =3*PI()/2**Result**: 4.71238898

**Syntax**: =2*PI()*12**Result**: 75.39822369

**Syntax**: =PI()/2**Result**: 1.570796327

**Syntax**: =PI()*4^2**Result**: 50.26548246

**Example 2:**

To convert an angle measured in radians that is in terms of π, the DEGREES function can be used to get the corresponding angle in degrees:

**Syntax**: =DEGREES(A2*PI())

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

**Syntax**: =DEGREES(A2*PI())**Result**: 360

**Syntax**:=DEGREES(A2*PI())**Result**: 90

**Syntax**: =DEGREES(A2*PI())**Result**: 45

**Note**: The PI function returns the value of π (pi) accurate to 15 digits. The value of π represents a half-turn in radians and appears in many formulas relating to the circle.