We all know that data validation is a very useful feature in Excel. You can use data validation to create a drop-down list in a cell and limit the values user can enter. But, do you know that you can use data validation in a multitude of ways to prevent users from entering wrong data?
Here is a practical application: Prevent users from entering duplicate values in a range of cells.
For eg. you are making an invoice. Wouldn’t it be cool if Excel prompted you when you enter a duplicate line item so that increase the item quantity instead of repeating it.
Here is a 3 step tutorial to do just that.
Step 1: Identify the range of cells where you want only unique values to be entered
This is simple. All you have to do is find the range where you want to control the user input. Lets say the range is B4:B11
Step 2: Set up Data Validation to prevent duplicate entries
Select the range (B4:B11) and go to data validation (Excel 2007: Data Ribbon > Data Validation, or press ALT+AVV)
Now, specify the validation type as “Custom”, this will allow us to use formulas to check for valid data. In our case, we need check if a particular entry is duplicated in the range B4:B11. This can be easily done using COUNTIF formula [learn COUNTIF Formula in plain English].
Go to the formula field and type the countif formula like this: =COUNTIF($B$4:$B$11,B4)<=1
Also, you can set up the “Error Alert” so that you can show a custom message when a duplicate value is typed, like “You have already added that product” message.

Once you set up error message, it will show up like this:

Step 3: Sit back and Relax
The third step is all too familiar. Now that you have prevented duplicate entries in your spreadsheets you can sit back and relax. May be read a few more spreadcheats.
More kickass stuff on data validation (and working with duplicates) using excel
There are a ton of useful articles on the site related to data validation and working with duplicates using excel. Here is a sample. Get started and learn something useful today.
- Data Validation Tricks in Excel [with downloadable tutorial]
- Remove Duplicate Values from a Range in Excel
- Using Array formulas to find if a list has duplicates
- Working with duplicate items in Excel [several examples]
- Examples & Articles on Excel Data Validation
This post is part of our spreadcheats series (yes, the series is still going after one year 😛 )

















25 Responses to “Display Alerts in Dashboards to Grab User Attention [Quick Tip]”
I prefer the red,grey,light grey,black icon set. I've also used in-cell pie charts from Fabrice's Sparklines for Excel as an alert which could also provide another piece of information.
I prefer the red,grey,light grey,black icon set. I've also used in-cell pie charts from Fabrice's Sparklines for Excel as an alert which can also provide another piece of information.
For Excel 2007, your formula should do the same as the Excel 2003 version, so that non-alert rows are blank - if they are 0, the unnecessary green icon will show
Hi Chandoo,
Nice Post !! just to add something for EXL 2003, we can also 4 Ifs and link to the alert data
For Ex: If we have alert data in Cell A2 and want to split in 4 orders namely <25%, 25-50%, 50-75% and 75%< then we can following formula and put fonts as you have suggested :
=IF(A2<0.25,CHAR(153),IF(A2<=0.5,CHAR(155),IF(A2=0.76,CHAR(152)))))
And then using Conditional Formating we can dashboard reflected on different COLOURS as per their respective alert.
Best Regards
Rohit1409
Hi Chandoo,
Nice Post !!! just to add something for EXL 2003, we can also 4 Ifs and link to the alert data
For Ex: If we have alert data in Cell A2 and want to split in 4 orders namely <25%, 25-50%, 50-75% and 75%< then we can following formula and put fonts as you have suggested :
=IF(A2<0.25,CHAR(153),IF(A2<=0.5,CHAR(155),IF(A2=0.76,CHAR(152)))))
And then using Conditional Formating we can dashboard reflected on different COLOURS as per their respective alert.
Best Regards
Rohit1409
The Complete formula [Don't Know how it got cut ]
=IF(A2<0.25,CHAR(153),IF(A2<=0.5,CHAR(155),IF(A2=0.76,CHAR(152)))))
PS : Use in single line [I have split it to avoid cuts 😉 ]
Hi Chandoo..
why it is not displaying the complete formula..
anyways here is the balance
"=IF(A2<0.25,CHAR(153), IF(A2<=0.5,CHAR(155), IF(A2=0.76,CHAR(152)))))"
@Rohit... your formulas are fine. Just that the width of comment area is fixed and hence my website is cropping it at 640pixels. I just edited your formula and added few white spaces so that it wraps nicely.
Very good idea btw.. kudos!
Hi,
Maybe just go for 'bold' ; 'underline' or 'italic' to draw the users attention? Those methods (if those can be called methods) are used cross media type (books, journals, blogs, billboards, ...) to guide the readers eye to valuable information.
Just a basic thought
@Tom.. good idea..
[...] has a very nice writeup on how to add such alerts to dashboard sheets. Possibly related posts: (automatically generated)Divide your data set into workbooksHow to enforce [...]
Hi Chandoo,
You certainly grabbed my attention! although I wasn't sure what my brother (Suresh) and cousin (Shyam) were doing right, and I was doing wrong? 😉
I love your blog btw - Many thanks for all your hard work in unravelling the secrets and mysteries of Excel!
Best regards
Ramesh
I thought I saw an advertisment for a book about learning excel called excel himalaya or something. It cost about 35.00 us money but seemed to have the things I need to have my admin assistant to start to use. I was hoping to start with this book and then send her to school if she shows some interest and aptitude. Any help on this would be appreciated. Thanks
Great web site and information!!!!
@Jeff... checkout http://chandoo.org/wp/2010/08/25/excel-everest-review/
thanks, your website is awesome!
[...] Alerts to highlight focus areas [...]
[...] There are lots of numbers in this dashboard. I would suggest adding few more visualizations like showing indicators or applying conditional formatting or replacing a table with a chart. This would reduce the [...]
[...] is the same technique as alert icons in dashboard. Just that I also showed green [...]
[...] is the same technique as alert icons in dashboard. Just that I also showed green [...]
Hi Chandoo
Firstly thanks for all the cool tips on how to use Excel better.
I am new to the site and have a question which you may be able to assist with but dont know if these comment boxes are the best way of asking ?
I am looking at assets and trying to calculate the depreciation total by taking a year (say 2010) adding the expected life of the asset (say 10 years) then comparing that to a future date (say 2015) using an IF statement. The calculation in normal is - IF((year in col B (2010) plus 10years)>year 2015, add a years depreciation, otherwise leave blank). The converted date value does not appear able to add 10 years in order to compare it to 2015. Am I missing something ?
I use the “IF” Statement in conjunction with Conditional Formatting in MS Excel to give verbiage to alert one of a required action, dependant on a review date. This makes a visual stimulus, plus it clues one as to what the conditional format is trying to warn you about and what follow-up actions are required.
Wow, I'm really impressed with dashboards. I had no idea this stuff was even possible with excel. I'd like to offer an interactive dashboard to my customers, showing analytics of their data. I have a .pdf file with the datapoints. I'd like them to enter the data on my website, and be able to see their data. Is something like that possible.
Hi Chandoo,
I've recently purchased the package for both templates.
In the portfolio dashboard,under the calculations worksheet, I'm attempting to change the date range in the gantt chart to show only the range of the project that starts in late 2013. How do I do this?
Thanks
Adam
[...] is the same technique as alert icons in dashboard. Just that I also showed green [...]
Hi Chandoo,
I'm new at Excel Dashboard and found your blog really useful and helpful! It's very nice of you that you dedicate your time to do this.
Could you please explain how can I use Alerts based on dates on a Dashboar?
For example, if a target date is coming closer to the actual date, the alert is yellow or red.
I'd really appreciate some help!
Thank you
Where can I download the file Excel of Averall Statistics ???
Thanks a lot.