The LET Function
LET Function
The LET function is another recent feature added by Microsoft and only available in Microsoft 365. The function is not designed to perform a particular calculation but is used to simplify complex formulas by allowing the user to declare variables. Anyone who has written programming code would be familiar with this idea of declaring variables.
The primary benefits of this function include:
Calculation Performance Time - Being able to have a complex formula only calculate a section of formula once and store the answers will speed up formulas.
Simplifying Formulas - Using Let makes understanding and writing complex formulas much easier as you can name the variables using a name that explains what you are doing. This works very similar to named ranges but is only available in the formula vs. the entire workbook.
Lets go ahead and jump into some of the great resources on the web for understanding how the LET formula works. The resources listed below will help you understand how LET works and why you should become more familiar with this new function. Before I jump into my list of great LET resources I recommend you check out the link from Microsoft explaning how the LET function works.
LET function - Office Support (microsoft.com)
VIDEO RESOURCES
Below are a few good videos to watch that will help you understand how LET works and when you should use it:
The first video is From Lelia Gharani and explains how we would use LET in formulas and shows how it can substantially improve calculation times for complex formulas. In particular complex formulas that use Dynamic Arrays.
The second video I recommend is from Excel on Fire and Oz du Soleil. In this video Oz walks through Let in what he calls 3 acts. As always he does a great job of explaining things in his unique storytelling style.
The Third video is by my Mynda Treacy and she discusses LET and how it improves readability, and performance.
The next few videos show different real-life examples using LET including a crazy formula using LET and LAMBDA by Mike Girvin at “Excel is Fun”
EXCEL LET ARTICLES
In this section we will discuss a few great articles/blogs that explain how LET works and examples of how we can use it in our work.
The first article is from ExcelJet and explains the basic syntax of the formula and gives 3 examples of how one would use LET. When it comes to understanding formula syntax for any Excel formula and seeing practical examples of how to use the formula ExcelJet should be on your favorites list.
https://exceljet.net/excel-functions/excel-let-function
The second article was written by Svetlana Cheusheva at ablebits.com.
Excel LET function with formula examples (ablebits.com)
This article not only explains the function but explains the advantages for using LET and also provides simple guidelines and a sample workbook for making your LET formulas easier to use. As we start learning LET one of the most important things we need to learn is how to write good code. Anyone who has spent anytime working in Excel and especially working with other peoples workbooks will appreciate this section on best practices for using Let.
The third article is from Exceluser.com and is written by Charley Kyd.
How to Use Excel's LET Function - ExcelUser.com
In this article he goes so far as to say “The LET function is the most powerful function that Microsoft has released for Excel in Years.” I am not sure I would go that far with the LET function but it is a powerful function and this article does a great job of showing how you should write LET formulas and has a section on best practices and includes a sample workbook for downloading.
The last article is by Chris Newman at TheSpreadsheetGuru.
All About Excel's New LET Function — TheSpreadsheetGuru
Similar to the above articles this one gives a brief overview of how the function works and then spends most of the time focusing on best practices for writing LET functions.
CONCLUSION
The LET function is an exciting addition to Excel as not only does it make writing complex formulas easier but it also speeds up calculation time and makes reading and understanding them easier for people reviewing someone else’s work. I highly recommend taking the time to learn this function and incorporate it in your workbooks when working with complex formulas. As you start incorporating it in your workbook please take the time to learn best practices for making your formulas easy to read as that will make everyone’s life easier as they work with your workbooks.
Leave your thoughts below on the blog or how you might use the LET function in your day to day work.