# How to use PI in Excel

Of all of the formulas in Excel to help calculate values, PI is one of the more simple ones, but also incredibly useful. PI is a value that depending on how far you want to go with it has a fair bit to memorise. A quick Google search will obviously provide you with as many numbers as you want, but if you are using PI in Excel to perform further calculations having a formula on hand makes life a lot easier.

In this simple guide we will cover how to use PI in Excel, and how to combine it with additional formulas to make it really useful.

We will cover:

- The formula
- An example of using PI

Let’s get started.

## The PI Formula

This one is incredibly simple. The entire formula for PI is as follows:

**=PI()**

That’s it! It requires no arguments so it is literally as simple as that. An example output is below:

The output itself depends on the formatting of the cell and how many decimals we are looking to display, but one thing to keep in mind is that in Excel it only ever displays 14 points of PI. As you can see in the below outputs, if we were to extend the number of displayed decimals up to 20, they just start displaying zeros:

Now that we have the (incredibly simple) formula out of the way, let’s look at a quick example of combining this with additional values.

## Using PI in Excel to calculate area

As PI is used a lot in calculations, let’s look at one of the most common – calculating the area of a circle. If we are provided with a radius value, we then simply need to expand our formula to the following:

**=PI()*RADIUS^2**

The below table displays a range of different supplied radius values, along with the area output:

As we can see, by simply using PI() as the formula it makes life a fair bit easier than typing out 3.14…. and so on in the formula itself.

This sums up our quick and easy guide on using PI in Excel. For more handy guides on working with Excel, be sure to check out our Excel Tips page.