Factorial in Excel

Calculating Factorial in Excel using FACT

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  • Excel

In this simple guide, we are going to explain how calculate a factorial in Excel using any given number by using the built in FACT function.

This guide will cover:

  • What is a factorial?
  • The FACT function, and formula syntax
  • Example of calculating Factorial in Excel

What is a Factorial?

A Factorial is a function in maths that takes a number, and then multiplies it by every whole number below it, until it reaches zero.

In mathematical equations it it represented by an exclamation mark following the number – for example 8!

Let’s look at a few basic examples of this:

4! would mean take 4, and times that by 3, which gives us 12. Take that number and times it by 2 – giving us 24. Then take that and times by 1, which stays at 24.

Visually, that would be represented in the calculation as:

4! = 4 x 3 x 2 x 1

Things do start to get a bit more complex when working with higher values. 10! for example would be:

10! = 10 x 9 x 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1

This doesn’t look so bad, but the resulting value ends up being over 3 million at 3,628,800! Once we start looking at values this high working with a simple formula can make life a lot easier.

Working with factorials can be very useful in both a range of basic real life scenarios, and within other areas of mathematics including algebra. For the sake of this tutorial we will keep things simple and just look at the most basic Factorial formulas such as those outlined above. For a more detailed explanation on how to work with factorials, including some problems to solve, Khan Academy has a great set of guides on this topic.

Let’s now take a look at how to use Excel to simplify this process.

Using the Excel FACT function

As mentioned, once we start working with higher numbers manually calculating the factorial can be a bit more challenging. Luckily Excel has a built in function called FACT that makes it nice and easy.

The syntax is simply as follows:

=FACT(number)

Examples of calculating Factorial in Excel

Looking at our example above of 4!, let’s see how this would work in Excel.

Using the formula of =FACT(4), we would simply get a result of 24:

Excel FACT formula

This formula is particularly useful when we start working with numbers in the teens and above. As you can see in the below table, the number of calculations required, and the scale of the values themselves grow rapidly when we go beyond a factorial calculation of 10 and above:

Calculating various factorial values in excel

As we can see, these numbers go well and truly into the millions, billions and beyond very quickly! Using a quick and easy formula such as FACT is definitely preferable to any kind of manual calculation!

This sums up our guide on how to calculate the factorial of a number in Excel using the FACT function. As we can see, Excel provides some very handy and easy to use formulas to simplify mathematical calculations.

For more tips and tutorials on using Excels built in functions be sure to check out our Excel Tips page