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 😛 )
















24 Responses
I’d suggest simply using the subtotal function and filtering the data using the Win/Loss column. You get the same results and the formula is more comprehensible.
@John
That is one option.
There are times however when you want to see the whole data table or a filtered subset and still want to produce summary reports against an unfiltered field.
Is there a particular reason why you are using a comma and the unary (–) operator for the second array in the SUMPRODUCT formula? It seems to work the same if you were to string the arrays together using the asterisk (*). The advantage is that SUMPRODUCT treats the entire string of arrays as a single array.
@Mathew
Your correct, There is no difference.
I thought it may have been easier to explain this method.
Is there a way to do this on a large set of data? As in ~100,000 rows? When I try I get an error because the formula becomes too long. It says the max length of a formula is 8,192 characters. Excel 2010.
How do I incorporate a specific text within a cell for the second array. For instance, – -(C7:C13=”Apple”)
when I chose a specific text the formula does not work.
@RB
I am not sure what is the issue as if I use the sample data in the post the following work fine
Count:
=SUMPRODUCT(SUBTOTAL(3,OFFSET(C7:C13,ROW(C7:C13)-MIN(ROW(C7:C13)),,1)), –(C7:C13=”L”))
Sum:
=SUMPRODUCT(SUBTOTAL(3,OFFSET(C7:C13,ROW(C7:C13)-MIN(ROW(C7:C13)),,1)),(C7:C13=”L”)*(D7:D13))
You may want to check that there are no leading or trailing spaces in your list of Apples
I should have given a better explanation. Heres my situation. I have a column with cells filled with names like Column 1, Column 2, Pier 1, Pier 2, etc. If the cell just contained Pier and searched for that it works. But because it has other characters in the cell its not recognizing the pier. So how can I extract specific characters of a string of text in this formula?
Hopefully this was a better explanation
Hello-
This formula works pretty well for me except that it slow down excel and prevents some of my macros from working. I was wondering if there was a way to program this in VBA so that excel isn’t always trying to recalculate it. I would like to use a push of a button to get it to run then paste in a cell.
Thanks!
I am trying to sum filtered data in a column, but would want to ignore the negative values in the column. How to go about doing this?
@Akshay
Why not just add a filter to that column to only show the values greater than zero?
The negative values are required for reporting purposes, but their effect on the total is distorting the required output. Please advise.
@Akshay
I’d suggest making a post in the Chandoo.org Forums
http://forum.chandoo.org/
Attach a sample file to simplify the task
I have this working for counting and summing, however, I have a list and for the second array, I need a criteria. That is, I’m looking for b13:b200=”01.??.??” or =left((a1,2) or something like that. These types of criteria matches do not appear to work as I get a blank as a result.
Thanks!
@Bob
As your formula b13:b200=”01.??.??” looks like you are trying to check the first day of the month of the range
What about trying Day(B13:B200)=1
Hai Experts,
i understood this formula well and working fine in MS Excel 2013
but when the same am trying to place in google Spreadsheet it shows error as
“SUMPRODUCT has mismatched range sizes. Expected row count: 1. column count: 1. Actual row count: 2014, column count: 1.” and as a result #VALUE! Appears in cell.
Can anyone please help me how would i get it done in Google Spread sheet
or is there any other formula as a substitute for this.
Thank you very much.
thanks for providing this.. but why does excel keeps on prompting Circular referencing in cell D3?
@Vivek
I don’t know
I just downloaded the file and it is working fine and not showing that error
Goto the Formulas, Calculation Options Tab and check that Calculation is set to Automatic
What version of Excel and Windows are you using ?
I know that this forum is for MS Excel, but I am trying to help someone who is working in Google Sheets. The below formula works in Excel but Google Sheets returns:
“SUMPRODUCT has mismatched range sizes. Expected row count: 1. column count: 1. Actual row count: 39000, column count: 1.” and as a result #VALUE! Appears in cell.
This is the same problem asked by Srichirin above. Does anyone know if there is a formula for Google Sheets that will replicate what MS Excel does?
=SUMPRODUCT(SUBTOTAL(3,OFFSET($C$6:$C$39500,ROW($C$6:$C$39500)-MIN(ROW($C$6:$C$39500)),,1)),- -($C$6:$C$39500=H1),($D$6:$D$39500))
Trying to find a SUMPRODUCT formula that counts the word Closed by date for the last 7 days in a filtered list.
=COUNTIF(M:M,”>”&TODAY()-7) works ok for unfiltered count Column M contains Closure dates (blank if open) and Column L is Status Open or Closed
@ Terry
Please ask the question at the Chandoo.org Forums
https://chandoo.org/forum/
Please attach a sample file to ensure a quicker more accurate answer
I used this formula and worked like a charm! But, now I’ve been requested to use it but adding not one but two criteria in the same formula. For instance the sum I was doing added negative and positive numbers. I’ve been asked to use the exact same formula but adding that only positive numbers were considered… any idea on how to do this?
How exactly do you do sum filtered cells when two criteria are need not just one?
Thank you so much brother literally I have been struggling since morning to get the sum of the filtered category, however, after reading your blog attentively i got my solution, so thanks a lot once again.