Highlight duplicates in a filtered Excel Table

Author: Oscar Cronquist Article last updated on February 03, 2020

Highlight duplicates in a filtered Excel Table 1

The image above demonstrates a conditional formatting formula applied to an Excel Table containing random data. The Excel Table has been filtered to show only records for January 2012.

There is a built-in function in Excel that lets you highlight duplicates, however, that won't work properly if you have filtered the data.

The image above shows the built-in tool highlighting duplicate items. But one item exists only once in the filtered data, however, it is highlighted as a duplicate.

The reason is that there is another item not showing in the filtered table. You need to rely on a custom conditional formatting formula if you want it to compare only filtered visible values.

Note, Conditional formatting is volatile and may slow down your worksheet considerably.

Build an Excel Table

The reason I am using an Excel Table is that the conditional formatting adjusts automatically if you add or delete records. It also uses structured references so there is no need to change cell references in the formula.

The disadvantage is that you have to use the INDIRECT function each time you reference the Excel Table in the CF formula, it is not a big deal but it is worth noting.

Select any cell in your data set.
Press short cut keys CTRL + T to open the "Create Table" dialog box.
Enable the checkbox if the columns in the data set have header names.
Press with left mouse button on OK button to apply.

Create a new conditional formatting rule

Select table column "Description".
Go to the "Home" tab on the ribbon.
Press with left mouse button on the "Conditional formatting" button.
Press with left mouse button on "New Rule..".
Press with left mouse button on "Use a formula to determine which cells to format".
Copy this conditional formatting formula:
=SUM(COUNTIF(INDIRECT("Table2[@Description]"), IF(SUBTOTAL(3, OFFSET(INDIRECT("Table2[Description]"), MATCH(ROW(INDIRECT("Table2[Description]")), ROW(INDIRECT("Table2[Description]")))-1, 0, 1)), INDIRECT("Table2[Description]"), "")))>1
Paste to "Format values where this formula is true:". I will explain the formula later in this article.
Press with left mouse button on the "Format..." button.
Go to tab "Fill".
Pick a color.
Press with left mouse button on OK button.
Press with left mouse button on OK button again.

Explaining CF formula in cell C211

This Conditional Formatting formula highlights cells that have a duplicate in a filtered Excel Table, note that it will not be highlighted if a duplicate exists outside the filtered values (not visible).

Step 1 - Create an array from 1 to n

The INDIRECT function makes it possible to use a reference to an Excel Table inside a Conditional Formatting formula. This article explains it in greater detail: How to use an Excel Table name in Data Validation Lists and Conditional Formatting formulas

The ROW function converts a cell reference to the corresponding row numbers which is useful when you want to create an array.

The MATCH function is utilized in this example to create an array that contains a sequence that begins with 1 and increments with one up to the number of values in the array.

MATCH(ROW(INDIRECT("Table2[Description]")), ROW(INDIRECT("Table2[Description]"))

becomes

MATCH(ROW(C206:C227), ROW(C206:C227))

becomes

MATCH({3; 4; ... 383; 384}, {3; 4; ... 383; 384})

and returns

{1; 2; 3; ... 380; 381}.

The Excel Table has 381 records and the size of the array matches that number.

Step 2 - Modify array

This workaround makes it possible to use an array of values in a SUBTOTAL function, the OFFSET function splits the array into smaller arrays with only one value in each array.

OFFSET(reference,rows,columns,[height],[width])

It returns error values, however, the SUBTOTAL function can calculate these values anyway.

OFFSET(INDIRECT("Table2[Description]"), MATCH(ROW(INDIRECT("Table2[Description]")), ROW(INDIRECT("Table2[Description]")))-1, 0, 1)

becomes

OFFSET(INDIRECT("Table2[Description]"), {1; 2; 3; ... 380; 381}-1, 0, 1)

becomes

{0; 1; 2; ... ; 379; 380}

and returns

{#VALUE!; #VALUE!; #VALUE!; ... ; #VALUE!; #VALUE!}

Step 3 - Identify visible values

The first argument in the SUBTOTAL function is 3 and represents the COUNTA function meaning it will count cells that are not empty.

The SUBTOTAL function will actually return an array with this setup which is very handy in this situation.

SUBTOTAL(3, OFFSET(INDIRECT("Table2[Description]"), MATCH(ROW(INDIRECT("Table2[Description]")), ROW(INDIRECT("Table2[Description]")))-1, 0, 1))

becomes

SUBTOTAL(3, {#VALUE!; #VALUE!; #VALUE!; ... ; #VALUE!; #VALUE!})

and returns {0; 0; 0; ... ; 0; 0}. 0 (zero) represents a hidden value and 1 is visible.

Step 4 - Create an array containing visible values

The IF function replaces 0 (zero) with nothing "" and 1 with the actual corresponding value.

IF(SUBTOTAL(3, OFFSET(INDIRECT("Table2[Description]"), MATCH(ROW(INDIRECT("Table2[Description]")), ROW(INDIRECT("Table2[Description]")))-1, 0, 1)), INDIRECT("Table2[Description]"), "")

becomes

IF({0; 0; 0; ... ; 0; 0}, INDIRECT("Table2[Description]"), "")

and returns {""; ""; ""; ... ; ""; ""}.

Step 5 - Check the number of times the current value exists across visible values

The COUNTIF function will return an array with this setup which we then can use to calculate a total. The reason we don't change the arguments with each other is that the range argument will not accept an array based on calculations.

COUNTIF(range, criteria)

COUNTIF(INDIRECT("Table2[@Description]"), IF(SUBTOTAL(3, OFFSET(INDIRECT("Table2[Description]"), MATCH(ROW(INDIRECT("Table2[Description]")), ROW(INDIRECT("Table2[Description]")))-1, 0, 1)), INDIRECT("Table2[Description]"), ""))

becomes

COUNTIF(INDIRECT("Table2[@Description]"), {""; ""; ""; ... ; ""; ""})

becomes

COUNTIF("Chez Quiz", {""; ""; ""; ... ; ""; ""})

and returns {0; 0; 0; ... ; 0; 0}. The entire array is not shown, however, it contains a few 1's as well.

Step 6 - Calculate a total

The SUM function adds all numbers in the array and returns a total.

SUM(COUNTIF(INDIRECT("Table2[@Description]"), IF(SUBTOTAL(3, OFFSET(INDIRECT("Table2[Description]"), MATCH(ROW(INDIRECT("Table2[Description]")), ROW(INDIRECT("Table2[Description]")))-1, 0, 1)), INDIRECT("Table2[Description]"), "")))

becomes

SUM({0; 0; 0; ... ; 0; 0})

and returns 2.

Step 7 - Check if value is larger than 1

The > larger than character is a logical operator that lets you compare values, it will return a boolean value TRUE or FALSE based on the outcome. The Conditional Formatting formula uses the boolean function to determine if the cell values should be highlighted or not.

becomes

2>1

and returns True. Cell C211 is highlighted.

Get the Excel file

Highlight-duplicates-in-a-filtered-table.xlsx

Cf duplicates category

Highlight duplicate records
This article shows you how to easily identify duplicate rows or records in a list. What's on this webpage Highlight […]

Highlight duplicates with same date, week or month
The image above demonstrates a conditional formatting formula that highlights duplicate items based on date. The first instance is not highlighted, […]

Highlight duplicate values in a cell range
The following conditional formula highlights only the second instance or more of a value in a cell range. Conditional formatting […]

See all articles in 'cf duplicates' category

Conditional formatting category

Count Conditionally Formatted cells
This article explains how to count cells highlighted with Conditional Formatting (CF). The image above shows data in cell range […]

Highlight overlapping date ranges using conditional formatting
The image above demonstrates a conditional formatting formula that colors a record if there is at least one record that […]

Highlight records based on overlapping date ranges and a condition
adam asks: Hi, I have a situation where I want to count if this value is duplicate and if it […]

See all articles in 'conditional formatting' category

Table category

How to use an Excel Table name in Data Validation Lists and Conditional Formatting formulas
This article demonstrates different ways to reference an Excel defined Table in a drop-down list and Conditional Formatting. There are […]

Extract unique distinct values in a filtered list
This article demonstrates two formulas that extract distinct values from a filtered Excel Table, one formula for Excel 365 subscribers […]

Count unique distinct values in a filtered Excel defined Table
This article demonstrates a formula that counts unique distinct values filtered from an Excel defined Table. Debra Dalgleish described in […]

See all articles in 'table' category

Functions in this article

SUM COUNTIF INDIRECT IF SUBTOTAL OFFSET MATCH ROW

More than 1300 Excel formulas

How to use Excel Tables

Create an Excel Table

Conditional Formatting categories

Highlight Cells Rules Top/Bottom Rules Conditional Formatting features Basic Conditional Formatting formulas Conditional Formatting Partial match Highlight unique distinct values/records Highlight duplicates Comparing lists Highlight largest/smallest number Highlight dates Conditional Formatting examples

Excel categories

Home page

Latest updated articles.

Excel Functions

More than 300 Excel functions with detailed information including syntax, arguments, return values, and examples for most of the functions used in Excel formulas.

Excel Formulas

More than 1300 formulas organized in subcategories.

Excel Tables

Excel Tables simplifies your work with data, adding or removing data, filtering, totals, sorting, enhance readability using cell formatting, cell references, formulas, and more.

Advanced Filter

Allows you to filter data based on selected value , a given text, or other criteria. It also lets you filter existing data or move filtered values to a new location.

Data Validation

Lets you control what a user can type into a cell. It allows you to specifiy conditions and show a custom message if entered data is not valid.

Drop Down List

Lets the user work more efficiently by showing a list that the user can select a value from. This lets you control what is shown in the list and is faster than typing into a cell.

Named Ranges

Lets you name one or more cells, this makes it easier to find cells using the Name box, read and understand formulas containing names instead of cell references.

Excel Solver

The Excel Solver is a free add-in that uses objective cells, constraints based on formulas on a worksheet to perform what-if analysis and other decision problems like permutations and combinations.

Charts

An Excel feature that lets you visualize data in a graph.

Conditonal Formatting

Format cells or cell values based a condition or criteria, there a multiple built-in Conditional Formatting tools you can use or use a custom-made conditional formatting formula.

Pivot Tables

Lets you quickly summarize vast amounts of data in a very user-friendly way. This powerful Excel feature lets you then analyze, organize and categorize important data efficiently.

VBA

VBA stands for Visual Basic for Applications and is a computer programming language developed by Microsoft, it allows you to automate time-consuming tasks and create custom functions.

Macros

A program or subroutine built in VBA that anyone can create. Use the macro-recorder to quickly create your own VBA macros.

UDFs

UDF stands for User Defined Functions and is custom built functions anyone can create.

6 Responses to “Highlight duplicates in a filtered Excel Table”

Wesley says:

March 28, 2016 at 8:55 pm

Thank you for the great post! I had spent almost a full day searching for how to highlight duplicates in a filtered list. But I have one further question. I am filtering this based on duplicate dollar amounts. How could I add in a part of the function to only highlight the duplicate amounts over $900 in the filtered table?

Reply
Gene Haines says:

April 23, 2017 at 1:46 am

Oscar, Our company requires all employees to take 30 Mandatory Annual Courses. I have been tasked with streamlining the class schedule. I created in access a query that pulls all courses and personnel that are due to take these courses within 45 days. I export to excel and then sort on the courses and then the supervisor. After that I subtotal and get 30 subtotals for each course. The number of records in each subtotal course varies.

My max class size per course is 14 and the max number of people per supervisor is 5. How can I

Reply
Gene Haines says:

April 23, 2017 at 2:10 am

Oscar,

My company requires all employees to take Mandatory Annual Courses.
We have 30 courses.

I have been tasked with streamlining the class schedule. I have all courses listed along with the names of the personnel along with their department and supervisor. I sort by class name and then by supervisor. I then subtotal and get 30 separate subtotals per course. Number of records in each subtotal will vary.

My max class size is 14 and the most I can pull from each supervisor per class per course is 5.

How can I create a formula for each subtotal that will determine the number of classes based on a max class size of 14 and then assign the max number of personnel per class per supervisor of 5.

Example: Course Name: Active Shooter

42 people need to attend this class, There are 6 supervisors for these 42 people. On the surface it looks like 3 classes,however one supervisor has 16 people which would exceed the max per class of 5.

Any help is appreciated.

Regards

Gene Haines

Reply
- Oscar says:
  
  April 26, 2017 at 8:38 am
  
  Gene Haines,
  
  My max class size is 14 and the most I can pull from each supervisor per class per course is 5. 42 people need to attend this class, there are 6 supervisors for these 42 people.
  You only have 6 supervisors, don't you need more supervisors per class per course if your class is 42? If each supervisor has 5 people you get 6x5 = 30 people.
  This criteria is not met if your class is above 30 people?
no says:

May 6, 2021 at 10:53 pm

exactly what i was searching for. unfortunately way more cumbersome than i hoped, but a solution nevertheless. thanks a lot!

Reply
Gabriel says:

March 4, 2022 at 9:46 pm

Feliz tarde, el archivo de trabajo ya no está disponible. Podría volver a colocarlo??

Reply

How to comment

How to add a formula to your comment
<code>Insert your formula here.</code>

Convert less than and larger than signs
Use html character entities instead of less than and larger than signs.
< becomes < and > becomes >

How to add VBA code to your comment
[vb 1="vbnet" language=","]
Put your VBA code here.
[/vb]

How to add a picture to your comment:
Upload picture to postimage.org or imgur
Paste image link to your comment.

Contact Oscar

You can contact me through this contact form