Excel formulas acting slow? Today lets talk about optimizing & speeding up Excel formulas. Use these tips & ideas to super-charge your sluggish workbook. Use the best practices & formula guidelines described in this post to optimize your complex worksheet models & make them faster.

10 Tips to Optimize & Speed up Excel Formulas
1. Use tables to hold the data

Starting Excel 2007 you can keep all the related data in a table. For example call center data in our recent dashboard is kept in a table. Tables can be used in formulas with structural references, can be used as a source for pivot tables etc. And since tables grow & shrink as you add / remove data, none of your formulas need to be dynamic. As an example, if you have table called cs, then the formula sum(cs[column_name]) refers to sum of all values in the column_name of table cs. Even if you add more data to CS, the formula still works.
Resources to learn about Excel Tables:
- Introduction to Excel Tables – what are they and how to use them?
- Example: Customer Service Dashboard – Data & Calculations
2. Use named ranges, named formulas
By using names and named formulas, you can simplify your spreadsheet. Not only that, since named ranges & named formulas can hold arrays (ie lists of values), you can hold intermediate results or values that you need to refer many times in these named formulas. This will reduce the formula overhead and makes your workbooks faster.
Resources to learn about named ranges & named formulas:
- Excel School Program: In this comprehensive course, I talk about how to think about and write better formulas for data analysis work.
- Musings on Live Calendar [Excel Hero]
- Examples of Named Formulas – 2023 Calendar in Excel
3. Use Dynamic Arrays & Spill Ranges
Introduced in Excel 365, Dynamic Arrays allow us to build complex calculations with ease. I suggest incorporating new functions like:
- FILTER to fetch a list of values that meet one or more criteria.
- SORT to sort the values
- UNIQUE to eliminate duplicate values on the fly
- XLOOKUP to perform various lookups
- VSTACK / HSTACK to combine datasets
- TOCOL / TOROW to convert tables of data to single row or column formats
- # or Spill operator to manage spill ranges
Learn more about Dynamic Array functions here:
- Dynamic Array Functions – A deep introduction
- Dynamic Array Functions – how to use them [Video]
- How to use XLOOKUP
4. Use Pivot Tables
Many times, even when we do not need formulas we use them, because we can. Pivot tables are an excellent way to calculate a lot of summary values with few clicks. Once the pivot is built, you can refer to the pivot values with GETPIVOTDATA or simple cell references. This will reduce a lot of unnecessary calculations. If you are changing the data, you can just go to DATA ribbon and refresh all pivots in one go. This process works smoothly when you use tables to hold the data.
One of the reasons for slow workbooks is lot of data. Since, pivot tables are designed to work with lots of data, by using them, you can speed up your workbooks.
Resources to learn Pivot Tables:
5. Sort your data
One of the reasons for sluggish performance is that you are searching for something in a lot of un-sorted data. You are making Excel look for a needle in a hay-stack. Many times we inherit un-sorted data thru data imports. By sorting the data & using correct operators in lookup formulas, we can instantly speedup a sluggish workbook. If you feel that sorting the data is a pain, you can even automate it with Power Query or a sort procedure (thru a simple VBA macro).
Examples on Sorting:
- Remove duplicates & sort a list using Pivot Tables
- Use Power Query to pre-sort the data you are working with
6. Use Manual Calculation Mode
Speed is the hefty price you pay for complexity. But many times, we want our Excel workbooks to be complex, because only then they would reflect real world. In such cases, you can set formula calculations to manual mode.

Just press F9 whenever you want to run the formulas. Please note that Excel runs formulas whenever you save the file too.
7. Use Non-volatile formulas
There are a class of formulas in excel called as volatile formulas. These formulas are re-calculated whenever there is a change in the workbook. Examples of volatile formulas are RAND, NOW, TODAY, OFFSET etc. So when your worksheet has a lot of volatile formulas, any time you make a change all these formulas must be re-calculated. Thus, your worksheet becomes slow.
Solution? Simple, do not use volatile formulas. For example, instead of using OFFSET to construct a dynamic range, you can use INDEX. Since INDEX is non-volatile, it tends to be faster. Or better still, use a table.
Resources to learn more:
8. Keep formulas in a separate sheet
Formulas are the driving force behind any Excel workbook or model. By keeping all them in a separate worksheet(s), you minimize the chance of mistakes, omissions or repetitions. Debugging or investigating slow performance becomes an easy task when all formulas are in same place. I usually keep all the formulas in one sheet whenever I am designing a dashboard or complex workbook. This structure also helps me in thinking thru various calculations and planning the formulas in a structured way.
9. Write better formulas
Here are some guidelines that I follow when writing formulas.
- Built-in formulas tend to better than your own version – for example SUMIFS is easier to write and just as fast as SUMPRODUCT.
- Do not refer to entire column when you need just a few values. Do not write SUM(A:A), when you know values are only in A1:A10.
- IFERROR instead of lengthy IF(ISERROR formulas. Use IFERROR to simplify your error checking.
- Remove or Fix formula errors [how to, findout why formulas are not working]
- Use newer Dynamic Array formulas instead of old clunky array formulas
- Remove or Reduce references to other workbooks. Use Power Query instead.
- Remove any named ranges that result in error or missing links.
- Try to come up with alternative formulas: this not only sharpens your mind, but lets you discover better solutions.
- Do not calculate something if you do not need it.
- Do not calculate same thing twice. Use the first result second time too. Use LET for accomplishing this.
Resources to write better formulas:
- Introduction to SUMIFS formula
- Introduction to XLOOKUP formula
- How to use the new Dynamic Array functions in Excel
- Introduction to SUMPRODUCT formula
- Introduction to IFERROR formula
- Excel Formula Forensics
- Excel School program
10. Desperate times need desperate measures
Sometimes, no matter what you do, the workbook remains slow. Here are a few whacky ideas that I try in such cases:
- Replace formulas with values. I take a backup of the formulas. Then I select everything, CTRL+C, ALT+ESV (or CTRL Shift V). Done!
- Develop the workbook from scratch: Sometimes it helps to design the workbook afresh.
- Replace external data links with actual data: And import data by copy-pasting if needed.
- Reduce the functionality: See if the end user can live with fewer features in the workbook.
- Find an alternative solution: Trying to do everything in Excel is foolish. See if there is any external tool that can do this better & faster.
BONUS: Learn new formulas & play with them
Optimization is not a one-shot exercise. It is an ongoing-business. So you need to constantly learn new formulas, new uses & play with them. This way, you see new ways to improve a sluggish workbook. To begin with, explore our Formula homework & formula forensics pages and see how you solve these problems.
How do you speed-up your Excel formulas?
So how do you optimize & speed-up your Excel formulas? What techniques do you use? Please share using comments.

















28 Responses to “Pimp your comment boxes [because it is Friday]”
This borders on Excel soft-cell...er, soft-core...porn. My favorite kind.
Wow, that is pimp-TASTIC! I have a question, as a VBA n00b: additional comment boxes stay plain unless I "run" the macro. Is there a way to change all comments, going-forward?
hi Chandoo, well, I like the macro approach. For those who don't like it, there is another way: just add the "draw" toolbar to the shapes toolbar (via Custom etc), click on "edit comment", click on the auto-shape and then choose "draw" drop-down, --> modify auto-shape --> then you even can have a heart or a banner (I like the horizontal banner in in purple :-)) . in excel 2007, you have to add this custom menu that you choose via Excel Options --> Custom --> it is called "change/ modify auto-shape"!!!
best,
@Chandoo. Great Post 🙂
@Tim : the way the macro is coded, it must be run very time.
@Community: If someone has an idea to perform it when opening an existing excel, it should be nice.
@Community: if someone has some code to revamp the commentboxes on all sheets, please share it. 🙂
@Microsoft Excel-progammers: some pimpoptions for the commentboxes should be great.
Cheerio
Tom
For the auto run, please add the codes in workbook:
Private Sub Workbook_SheetActivate(ByVal Sh As Object)
Call Comments_Tom
End Sub
Wow, that was a lot of fun... Thanks Tom!
@Jeff... Now, 5000 people know about your favorite porn... 😛
@Tim ... you can write an event to handle the new comments. I wouldnt recommend it as it is really painful. another option is to use the macro suggested by Yukikomi. It will update comments everytime you activate the sheet.
@laguerriere: very cool 🙂
@Chandoo ... Thanks! This is good stuff. I combined your tip with a tip from Mark O'Brien, then assigned it to a button on Excel 2010's Quick Access Toolbar, to format comments AS I add them. I also like how Mark's code saves me the trouble of backspacing my name out of new comments:
Sub AppendToExistingComment()
'Source: Mark O'Brien at http://www.mrexcel.com/forum/showthread.php?t=57296
Dim oRange As Range
Dim oComment As Comment
Dim sText As String
'Use object variable to hold range.
Set oRange = ActiveCell
'Use object variable for comment
Set oComment = oRange.Comment
'text to be added to the comment box
sText = InputBox("Type text to be added:", "APPEND TO COMMENT TEXT")
If Len(sText) = 0 Then End
'If Active Cell has a comment then append new text to the end of the comment text
If Not oComment Is Nothing Then
sText = oComment.Text & vbNewLine & sText
oRange.Comment.Delete
End If
'Add a comment with the contents of sText
oRange.AddComment sText
DoEvents
Comments_Tom
End Sub
Thank you very much for the code, it seems to be working for the most part; I am having a problem however. Once the routine makes the corrections to the comment, the comment becomes invisible. By invisible, I mean that when I highlight my mouse over it, nothing appears. However, when I right click the cell and click 'edit comment' then the comment becomes visible and I enter edit mode. Upon clicking out of the comment, it simply vanishes again. I've tried to fix this problem by adding a .shape.visible = msoTrue but then every comment is always visible. o_O please advise...
Thank you,
Nick
@Nick- That is because the font color of the comment is white and when you select the color of selection is also white hence you can not see anything. Try to change the color code in the routine to something else. would work
Thanks for that! The code works perfectly!
[...] look at Format Excel Comment Boxes using VBA Macros | Chandoo.org - Learn Microsoft Excel Online [...]
@ Chandoo - code works great and the comments look super cool. But I have ran into a small issue. In the comments, I am inserting pictures. When I run the macro, for all comments which already have pictures; pictures are deleted. Pls help me retain the pics in comments.
[…] posted some code one of his readers submitted, it "pimps" your comment boxes from those boring black-text-on-yellow rectangles to something more professional and eye-pleasing. […]
love in it
Hi Tom,
This looks really excellent. I am however relatively new to macros / VBA codes so having copy pasted your code in the Developer mode of an Excel file, what are the next steps to use them? Can you please help? Just to recap, I opened a blank Excel workbook, clicked on Developer, copy pasted the comments code and saved the file to the desktop.
Now how do I go about using it to add comments to an existing file? My apologies for asking a question which may be basic to you great geniuses, but I am not there yet and aspire to get there.
Many thanks for helping me with next steps that I need to take so that I can now use the code.
Best Wishes
Deepak Dave, CMA, MBA, PMP
Senior Management Consultant
Dear Dave,
The best thing to do is to copy the macro in the personal.xls(x) file. The personal excel file will always be launched when you open excel so you can use it with every excelworkbook.
Read all about it on the page of Microsoft.
https://support.office.com/en-us/article/Copy-your-macros-to-a-Personal-Macro-Workbook-aa439b90-f836-4381-97f0-6e4c3f5ee566
Once you have the macro in the personal, you can 'call' the macro by the keyboardcombination 'alt+f8' and klik on the macroname.
Hope this clarifies the 'how to'. Good luck with your first steps in the wonderfull world of macro's.
Tom
Hi Tom,
Many thanks. I will try that out. Learning is fun and learning this stuff is even more amazing.
Best Wishes
Deepak Dave
There is a line 'Dim LArea As Long' which does not appear to be used. Have I missed something?
Dear Gary,
Correct the 'Dim LArea As Long' is indeed not relevant and can be deleted.
Tom
Excellent hack!
For some reason when I opened my file after using LibreOffice Calc, all comment boxes had changed to some arrow shape.
So this macro helped me from manually changing more than 5000 comments in a worksheet, or having to install some Excel extension.
I used it with the following attributes to get back old style comments:
It helped me from manually changing more than 5000 comments in a worksheet, or having to install some Excel extension.
.Shape.AutoShapeType = msoShapeRectangle
.Shape.TextFrame.Characters.Font.Name = "Calibri"
.Shape.TextFrame.Characters.Font.Size = 10
.Shape.TextFrame.AutoMargins = True
.Shape.TextFrame.AutoSize = True
Thanks a lot!
This was helpful, thank you
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the articles is really great : D. Good job, cheers
Is there code to add to this that will format a particular part of the comment (i.e. make the last sentence in the comment bold and in italics)?
This is fantastic!
How would I add auto-sizing to it?
I tried adding this:
.Shape.AutoSize = True but it gives me an error and as a novice at VBA I can't figure it out.
.Shape.TextFrame.AutoSize = True
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How should the code be changed in order to tun once for all worksheets in a workbook?