# How to Use PI in Excel

The PI function returns **3.14159265358979** -- the value of constant pi returned by the function is accurate to 15 digits -- in Microsoft Excel 2013 and Office 365. Use it in your formulas as PI(); the function does not accept any arguments. For example, you can use it to calculate the volume of a sphere. To get the most accurate result, format the cell that contains the formula and change the number of decimal places to **14**.

#### Step 1

Open the spreadsheet you want to edit in Excel 2013 or create a new spreadsheet. Type the radius of the sphere into one of the cells, or locate the cell that contains it.

#### Step 2

Right-click the cell where you want to display the volume of the sphere and choose **Format Cells** from the context menu. The Format Cells dialog displays with the **Number** tab selected by default.

#### Step 3

Select **Number** from the Category section to change the format of the cell and then type **14** into the **Decimal Places** field to use all 14 digits of constant pi in the formula. Click **OK**.You can select to use fewer digits, but Excel automatically approximates the value of pi -- for example, it returns **3.142** if you use three decimal places.

#### Step 4

[Format the cells further](http://www.ehow.com/how_8693097_apply-across-multiple-cells-excel.html) by changing the options on the **Alignment**, **Font**, **Border** and **Fill** tabs.

#### Step 5

Type **=4/3*PI()*Cell^3** into the **Formula** field and replace "*Cell*" with the cell that contains the radius of the sphere. Press **Enter** to calculate the volume of the sphere and display it in the selected cell.The **PI()** function returns the value of pi. "/" is the division operator, "*" is the multiplication operator and "^" is the power operator.

### Tips & Warnings

- To display the value of pi in a cell, type "=PI()" into the Formula field and press "Enter".
- To view the formula, instead of the result, in the selected cell, press "Ctrl-`".
- If you use fewer than 14 decimals, Excel approximates the value of pi, changing the results of your formulas.