CSV

Find Duplicates in Google Sheets Between Two Columns

When you have two lists in Google Sheets there finding matching values manually can quickly become frustrating. You may have one column which containing old customer records and another containing new leads or two lists of email addresses that need to be compared. In these situations Find Duplicates in Google Sheets Between Two Columns becomes important because you need to identify which values exist in both lists without checking every row manually.

If you have a small spreadsheet then Google Sheets can highlight matching values with Conditional Formatting or a simple COUNTIF formula. But when these lists become large, contain thousands of records or need to be cleaned and saved separately then a dedicated solution is the best option that makes the process much easier.

Why Need to Find Duplicates Between Two Columns?

Duplicate checking is normally required when you have two lists and it has been collected from different sources. You can understand this scenario by checking the given column below where column A has all existing customers records and Column B contains new customers records.

Here [email protected], [email protected] and [email protected] appear in both columns. Now the goal is not to find duplicates within the same column. However you want to compare two separate lists and identify the values they have in common.

This is useful when you are comparing old and new customer lists, checking duplicate email addresses, comparing employee or contact lists and comparing exported CRM data. The same problem becomes much harder when your spreadsheet contains thousands of rows.

What Does “Duplicate” Mean Between Two Columns?

When you are comparing two columns there is a duplicate that means the same value occurs in both columns and it could be multiple times. Check the example table below to understand better what counts duplicates.

Here you can clearly see in the above table John Smith and Sarah Jones are duplicates because they appear in both columns. However you need to be very careful with slightly different values like John Smith, john smith and John Smith when Find Duplicates in Google Sheets Between Two Columns.

These names may represent the same person but differences in capitalization or hidden spaces which can affect matching. So before comparing large datasets you must clean inconsistent values to improve the accuracy of your results.

Need to clean duplicate rows from a CSV file? Read our detailed guide How to Remove Duplicate Rows in a CSV File. This guide is useful when your Google Sheets data has already been exported to CSV and you need to remove repeated rows.

How to Find Duplicates in Google Sheets Between Two Columns Manually

If you only have a small dataset then using Google Sheets is enough for you and you can do this without using any additional software.

There is one simple approach which is Conditional Formatting with COUNTIF. For example if your data is in columns A and B then you can check whether each value in Column B also appears in Column A using this simple formula:

This checks the value in B2 column against the selected range in Column A. If the value exists Google Sheets can highlight it. You can then apply the rule to the required range in Column B. This method is useful for a quick visual check and similar COUNTIF techniques are commonly recommended for comparing two Google Sheets columns for duplicates.

What If You Need a List of the Duplicates?

Highlighting duplicates is not always enough in every case however you may also want a separate list containing only the matching values. For example a FILTER formula can return values from one column that also exist in another column:

This can be useful when you only need to see the matching values rather than highlight them in the original dataset. However these formulas become less convenient when you are dealing with large datasets, multiple CSV exports or data that ultimately needs to be cleaned and saved as a separate file.

Why Manual Google Sheets Methods Are Not Always Practical

Google Sheets methods are only useful if you are dealing with small datasets but they can become less practical when your spreadsheet contains thousands of records. So in this case you need to compare exported CSV files, removing duplicate records instead of simply highlighting them, compare multiple columns or repeat the cleanup process regularly.

In these cases formula based comparisons quickly become difficult to maintain as data volume grows particularly when a clean CSV file is ready for further use. Under such circumstances it is necessary to look for a dedicated tool that offers you a more practical way to Find Duplicates in Google Sheets Between Two Columns and safely remove all the duplicates without relying on lengthy manual checks.

Find Duplicates in Google Sheets Between Two Columns Automatically

If your data is already in Google Sheets you next step is to first export the relevant data as a CSV file. You can then use FreeViewer CSV Duplicate Remover Tool to automate the duplicate cleaning process.

This is very useful when you don’t want to create multiple formulas or manually examine highlighted cells. So rather than repeatedly checking values ​​against another column you can simply use a tool to process the CSV data and it will help you easily identify duplicate records more efficiently.

How to Use Tool to Find Duplicates in Google Sheets Between Two Columns

Use FreeViewer’s dedicated solution to Find Duplicates in Google Sheets Between Two Columns by exporting your data as CSV and processing it in just four simple steps.

Step 1: Download and Launch the Software

Download and launch FreeViewer Software on your Windows or macOS computer.

Step 2: Add CSV Files or Folder

Add your CSV files or folder containing the data you want to check for duplicates.

Step 3: Scan and Review CSV Data

Now you need to scan and review your CSV data to identify duplicate records quickly and accurately.

Step 4: Remove and Save Clean Data

Lastly you need to complete the removal process and save your clean CSV data for further use.

Which Method Should You Use to Find Duplicate Rows?

The best method to Find Duplicates in Google Sheets Between Two Columns depends on your data size and cleanup needs. If you have a small list Conditional Formatting, COUNTIF or FILTER is enough for you to identify matching values. But for large CSV datasets, repeated cleanup or multiple columns you need a professional approach. Check the table below for more insights.

Common Problems When Comparing Two Columns

When you Find Duplicates in Google Sheets Between Two Columns there data inconsistencies can affect the results even when your formula is correct. So before you highlight duplicates in Google Sheets between two columns you must check for common issues such as extra spaces, different capitalization, inconsistent formats and for blank cells.

Extra Spaces

You may think that these two values look identical but let me tell you that the second value contains additional space which can simply affect the matching.

• [email protected]

• [email protected] 

Different Capitalization

You may also have these two values where you find different capitalization. This is depending on the comparison method, inconsistent capitalization which can complicate duplicate detection.

• [email protected]

• [email protected]

Different Formats

Phone numbers are one of the common examples as these may represent the same number even though they are written differently.

• +1 555 123 4567

• 555-123-4567

Blank Cells

When learning how to find duplicates in Google Sheets between two columns you must remember that large spreadsheets generally contain empty rows or cells which should not automatically be treated as meaningful duplicate records.

Do you want to understand whether AI can work with your CSV data? If so then read our dedicated article on Can ChatGPT Analyze CSV Files? It will provide you another useful perspective on analyzing CSV data before deciding how to clean or process it.

Frequently Asked Questions

Q1. Can I find duplicates between two columns in Google Sheets?

Yes. You can compare two columns using Conditional Formatting, COUNTIF, FILTER or other Google Sheets functions as suggested above.

Q2. What formula finds duplicates between two columns in Google Sheets?

You can use this formula (=COUNTIF($A$2:$A$100,B2)>0). It will check whether the value in B2 appears in the selected range in Column A.

Q3. How do I find duplicate email addresses between two columns?

You need to place the two email lists in separate columns and compare one list against the other using COUNTIF or Conditional Formatting. If you have a large exported dataset then you need to save the data as CSV and process it using the FreeViewer solution.

Final Thoughts

Find Duplicates in Google Sheets Between Two Columns is simple when you are working with a small list and you can use formulas such as COUNTIF to quickly highlight matching values. But once your data grows or needs to be cleaned as a CSV file then depending on manual methods and maintaining formulas to review thousands of records quickly becomes inefficient. In that situation exporting your data and using FreeViewer Tool to find and remove repeated records in csv file provides you a more accurate and best solution to preparing a cleaner dataset for your next task.