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  • Writer's pictureMichael Sena

The Reasons Behind Slow Excel Files: 9 Causes and Solutions

Excel is the go-to software for organizing, analyzing, and manipulating data in today's data-driven world. With its versatile functionality, businesses and individuals alike rely on this powerful tool to simplify complex tasks and streamline daily operations.

But what happens when Excel starts to drag its heels, transforming from a time-saving hero to a sluggish adversary? In this expert round-up, we delve into the reasons behind slow Excel files, uncovering nine common culprits and offering practical solutions to restore your spreadsheets to their former glory.

Our panel of experts, boasting a wealth of knowledge and experience in the realm of data management and optimization, have generously shared their insights to help you tackle your Excel woes head-on.

From too many sheets and memory usage to file size, we'll explore the hidden pitfalls that could be wreaking havoc on your spreadsheets and provide valuable tips to optimize performance and efficiency. So grab a cup of coffee, settle in, and let's unlock the secrets to lightning-fast Excel files!

There Are Too Many Sheets

Trying to work with an Excel document that's too large can be extremely frustrating. This happened to me on a project at work recently. I had 35 sheets in one Excel document, and because of the number of sheets, it took a very long time to save and open the file each time I wanted to make changes.

It was especially bad when I tried scrolling across fresh sheets in the same file—there were so many sheets that it kept crashing my computer and preventing me from making any progress. Making sure you don't create more sheets than necessary in an Excel document is key to avoid any delays caused by slowness.

Antreas Koutis, Administrative Manager, Financer

Applying Colors

I remember the time I had a really extensive database in Excel and I attempted to make it more user-friendly by adding color to some columns. Well, it turned out to be a terrible idea. Just this little change made the file so slow that it was almost impossible to work with.

At first, I couldn't understand why it was happening, but after some research, I discovered that coloring cells or columns in Excel can significantly slow down the file, especially when working with an extensive database.

Apparently, the reason for this is that Excel recalculates every cell and formatting option each time a change is made to the file. So, the more formatting changes there are, the longer it takes for Excel to perform its calculations.

Natalia Brzezinska, Marketing and Outreach Manager, ePassportPhoto

Multiple Formulae

A reason that Excel runs slowly after a while is that I use multiple formulae that are intensive in processing. I have a lot of data to keep track of this and I also need to compare this information with other stats in figures around each sheet. Because of this, VLOOKUP has become essential for me, but unfortunately, the amount I need to use it has become excessive for the document.

To fix this, I had to split up the data into what was essential for that one document and try to not use this so often, but it became a real problem for me afterward because of data repetition between the documents, making it difficult to keep track of which data I had changed on one document and not the other.

Aiden Higgins, Senior Editor and Writer, The Broke Backpacker

Volatile Functions

Volatile functions may delay Excel. Excel recalculates volatile functions and worksheet formulas after changes. A worksheet with several volatile operations can slow processing. Consider a workbook containing a "Data" sheet with 10,000 rows and 20 columns of data.

The "Calculation" sheet uses "Data" formulas. Excel recalculates all formulas in the "Calculation" sheet when you change the file if you use a volatile function like NOW(). Data and algorithms can delay Excel.

Replace volatile functions with non-volatile ones or use VBA to automate formula recalculation. Replace NOW() with a non-volatile function like DATE(), which only recalculates when the worksheet or formula is used. Excel also allows manual calculation. Choose "Calculation Options" and "Manual" from "Formulas". Stopping Excel from recalculating formulas improves workbook performance.

Alice Hall, Co-founder and Creative Director, Rowen Homes

Many Complicated Calculations

Having too many complicated calculations in a single workbook can cause one example of Excel slowness. As the number of calculations and formulas increases, the workbook can become sluggish in responding, especially when working with large amounts of data. This can cause slow load times, delayed response times when making changes or updates to the workbook, and an overall decrease in productivity.

To address this issue, I recommend optimizing Excel formulas and calculations by using simpler formulas or breaking down complex calculations into smaller parts. It is helpful to reduce the amount of unnecessary formatting and data in the workbook and to close any other programs or files that are not needed while working in Excel to free up resources and improve performance.

Rows Filled With Complex Data

Excel is useful in several ways, but its scalability is lacking after you reach a certain point. The row limit is high, over one million, but depending on the type of data on the sheet, it can certainly slow down and lag well before that.

We've encountered this with our analytical data, particularly with our number and small graph measurements. After a certain point, I would say after around 30,000 rows, data tables struggle to communicate and adjust with number data. So Excel isn't a great option for data-centric analysis models.

After a certain point, we had to backlog much of our data because our sheets would offer the spinning loading wheel of trouble. After several attempts, we had to take relevant data and backlog most of it, all just to start again with a sheet that would actually load and function properly.

Large Data Sets

A high number of calculations, complex formulas, and too many worksheets can cause this. If you are dealing with data pulled from external sources such as databases or webpages, it can also slow down Excel, as it needs to establish a connection and pull in the relevant data each time.

Macros and Large File Overload

Many factors, including the number of formulas used in a single worksheet, the size of files being manipulated or saved through Excel, and excessive use of macros, cause overload.

If the overload is slowing down your Excel file, consider reducing the number of formulas and macros used, avoiding manipulating extensive files through Excel, or splitting the worksheet up into multiple smaller sheets.

Excessive Add-Ins

I experienced sluggish Excel firsthand in a previous job; I was part of a team that managed complex data with Excel and its add-ins. The sheer complexity of the data itself made it challenging to manipulate, and as we unconsciously started adding more and more add-ins, Excel started performing slower and slower.

We soon noticed signs of excessive usage, such as the lag time when manipulating cells in larger spreadsheets. Eventually, we identified the culprit to be our excessive use of add-ins: we did not need these for most daily tasks, so after removing some of them, Excel ran far more smoothly.


It's evident that optimizing your spreadsheets requires a delicate balance of data management, smart formula usage, and efficient formatting techniques.

To enhance your Excel experience, consider implementing the tips shared by our experts, such as minimizing the number of sheets, streamlining your use of color, optimizing your formulas, and being cautious with volatile functions.

Additionally, assess your add-ins, manage macros wisely, and avoid overloading your spreadsheets with unnecessary information. These steps will pave the way for a smoother, faster, and more productive experience with this powerful tool.

Remember, the key to maintaining efficient Excel files lies in continuous evaluation and optimization, so keep experimenting and refining your techniques to unlock the full potential of your spreadsheets.


1. Lack of awareness
2. Budgeting constraints
3. Status quo
4. Case study
5. Equilibrium
6. The remedy
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