# How to Use FACTDOUBLE Function in Excel (4 Examples)

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While dealing with Microsoft Excel, sometimes we need to calculate the double factorial of an integer. The FACTDOUBLE function is a built-in function that helps us to find the double factorial of an integer in Excel. Today, in this article, we will learn four examples of how to use the FACTDOUBLE function in Excel effectively with appropriate illustrations.

## FACTDOUBLE Function Overview

Syntax

The syntax of the FACTDOUBLE function is,

`=FACTDOUBLE(number)` Arguments Explanation

Arguments Required/Optional Explanation
number Required Returns a double factorial of that number.

Return Value

The FACTDOUBLE function returns a double factorial of a number.

Special Notes

We will calculate the double factorial of the Nth integer using the FACTDOUBLE function. Let’s have a look below to better understand.

• If the Nth integer is Odd,

=FACTDOUBLE(N)

=N*(N-2)*(N-4)*……*7*5*3*1

• If the Nth integer is Even,

=FACTDOUBLE(N)

=N*(N-2)*(N-4)*……*8*6*4*2

• For instance, we will calculate the double factorial of integer 7.

=FACTDOUBLE(7)

=7*5*3*1

=105

• The FACTDOUBLE function is available from Excel 2007 to the present version. This function is also available in Office 365. I have used Excel 2021 while writing this article.

Consider the following dataset. Let’s use this dataset to demonstrate what actions to take while using the FACTDOUBLE function. We will calculate the double factorial of an odd or even number, and calculate the factorial of a number as well, using the FACTDOUBLE function. We use nest the FACTDOUBLE and FLOOR functions to calculate the double factorial of an integer in Excel. Here’s an overview of the dataset for today’s task. ## 1. Applying the FACTDOUBLE Function to Calculate the Product of Odd Integers

In this example, we will calculate the double factorial of an odd integer using the FACTDOUBLE function. This is an easy and time-saving task as well. Let’s follow the instructions below to learn!

Steps:

• First of all, select cell C5 and write down the below FACTDOUBLE function in that cell. The function is,
`=FACTDOUBLE(B5)`

Where B5 is the number argument of the FACTDOUBLE function.

• After that, simply press Enter on your keyboard. As a result, you will get the double factorial of 15 which is the return of the product of the odd integers up to 15. Therefore, the return will be 2027025. • Further, apply the AutoFill tool for the formula with the FACTDOUBLE function to the rest of the cells in column C. ## 2. Using the FACTDOUBLE Function to Calculate the Product of Even Integers

Now, we will calculate the double factorial of an even integer using the FACTDOUBLE function. This is an easy and time-saving task as well. Let’s follow the instructions below to learn!

Steps:

• Insert the following formula in cell C5.
`=FACTDOUBLE(B5)`

Where B5 is the number argument of the FACTDOUBLE function.

• Afterward, simply hit Enter. Hence, you will get the double factorial of 16 which is the return of the product of the even integers up to 16. The return is 10321920. • After that, use the AutoFill feature with the FACTDOUBLE function for the rest of the cells in column C. ## 3. Utilizing the FACTDOUBLE Function to Calculate the Factorial of Integers

In this section, we will calculate the factorial of an integer by applying the FACTDOUBLE function. Firstly, the FACTDOUBLE function calculates the double factorial of an odd or even number. Secondly, the FACTDOUBLE function calculates the double factorial of a descending even or odd number. Afterward, these two functions will multiply the double factorials to get the factorial of a number. Let’s follow the instructions below to learn!

Steps:

• Write down the following formula in cell C5.
`=FACTDOUBLE(B5)*FACTDOUBLE(B5-1)`

Where the first B5 is the number argument of the first FACTDOUBLE Secondly, B5-1 is the number argument of the second FACTDOUBLE function.

• Hence, press Enter. After that, you will get the factorial of 10 which is the return of the product of all the integers up to 10. The return is 3628800. • After that, AutoFill the cells with the formula of the FACTDOUBLE function to the rest of the cells in column C. ## 4. Combining FACTDOUBLE and FLOOR Functions to Get Product of Integers

Last but not least, we will apply the FACTDOUBLE and FLOOR functions to calculate the double factorial of an integer in Excel. Firstly, the FLOOR function returns an integer value of a real number. Hence, the FACTDOUBLE function will convert that integer into a double factorial. Let’s follow the instructions below to learn!

Steps:

• Type the following formula in cell C5. The formula is,
`=FACTDOUBLE(FLOOR(B5,1))`
• Further, simply press Enter. As a result, you will get the double factorial of 7.89 which is the return of the functions. The return is 105. Formula Breakdown
• Inside the FLOOR function, B5 is the number argument, and 1 is the significance argument.
• FLOOR(B5,1) converts 89 into 7.
• After that, FACTDOUBLE(FLOOR(B5,1)) returns the double factorial of 7.
• Further, use the AutoFill tool for the rest of the cells in column C. ## Reasons Behind FACTDOUBLE Function Not Working in Excel

Errors When They Show
#VALUE! If the number is not numeric.
#NUM! If the number is negative(number <= -2).

## Conclusion

I hope all of the suitable examples mentioned above to use the FACTDOUBLE function will now provoke you to apply them in your Excel spreadsheets with more productivity. You are most welcome to feel free to comment if you have any questions or queries.

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Hi! I'm Md. Abdur Rahim Rasel. Welcome to my Profile. Currently, I am working and doing research on Microsoft Excel and here I will be posting articles related to this. I have completed my graduation in Naval Architecture and Marine Engineering(NAME) from Bangladesh University of Engineering and Technology(BUET). I have a passion for learning new things with my knowledge through perseverance and hard work.

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