How to Highlight Duplicates in Google Sheets: A Step-by-Step Guide


Sanskar Tiwari

How to Highlight Duplicates in Google Sheets

Dealing with duplicates in datasets can be a major headache, especially when you're dealing with large amounts of data. Google Sheets offers several powerful tools to help identify and manage duplicate entries, making your data cleaner and more efficient. In this guide, we'll walk you through the various methods to highlight duplicates in Google Sheets. Additionally, we'll introduce, a versatile tool that can enhance your spreadsheet tasks with even more functionality.

What Are Duplicates, and Why Remove Them?

Duplicates in data refer to repeated entries that may occur due to various reasons such as data entry errors, merging of records, or improper imports. These repetitions can skew your analysis, leading to inaccurate results. Identifying and removing duplicates is crucial for:
  • Ensuring the accuracy of your data.
  • Improving the performance of your analyses.
  • Preventing errors in decision-making processes.

Methods to Highlight Duplicates in Google Sheets

Step 1: Open Your Google Sheet

Begin by opening the Google Sheet document where you want to highlight duplicates. Make sure you have editing access to the document.
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Step 2: Select the Range of Data

Click and drag to select the range of cells where you suspect there are duplicates. If you want to check the entire sheet, click on the corner button left of column A and above row 1 to select all cells.
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Step 3: Use Conditional Formatting

  1. With the data selected, click on Format in the top menu.
  1. From the dropdown menu, select Conditional formatting.
  1. The Conditional Formatting sidebar will appear on the right side of your screen.
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Step 4: Set Up the Rule to Highlight Duplicates

  1. In the Format cells if dropdown, choose Custom formula is.
  1. Enter the formula to find duplicates. For a single column, use:Replace A:A and A1 with the column you are checking. For multiple columns, adjust the formula to match your data range.
    1. scssCopy code =countif(A:A, A1)>1
  1. Choose a formatting style (like a background color) that will make the duplicates stand out. Click on the Done button.
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Step 5: Review and Remove Duplicates

Once duplicates are highlighted, review them to ensure that these entries should indeed be considered duplicates. You may need to delete or merge data depending on your specific requirements.

2. Using Google Sheets Functions

For those who prefer working directly with functions, UNIQUE and COUNTIF are particularly useful.


  • Identify Unique Values: To extract a list of unique values from a range, use =UNIQUE(range).
  • Compare Against Original: This method requires a bit of manual comparison but is effective for smaller datasets.


  • Direct Identification: Create a new column next to your data. In the first cell of this new column, enter =COUNTIF(A:A, A1) and drag down.
  • Filter by Count: You can then filter this new column to show only values greater than 1, which indicates duplicates.

3. Google Apps Script

For advanced users, Google Apps Script provides a way to customize how you handle duplicates:
javascriptCopy code function highlightDuplicates() { var sheet = SpreadsheetApp.getActiveSpreadsheet().getActiveSheet(); var range = sheet.getDataRange(); var values = range.getValues(); for (var row in values) { var dataCount = {}; for (var col in values[row]) { var cellData = values[row][col]; if (dataCount[cellData]) { sheet.getRange(parseInt(row) + 1, parseInt(col) + 1).setBackground('yellow'); } else { dataCount[cellData] = true; } } } }
This script will highlight duplicates in every row of your Google Sheet.

Enhancing Google Sheets with

While Google Sheets provides robust tools for managing duplicates, integrating with a tool like can take your data handling to the next level. offers enhanced analytics, more sophisticated duplicate detection algorithms, and seamless integration with external data sources, making it an invaluable addition to your data management toolkit.
By connecting Google Sheets with, you can automate repetitive tasks, apply more complex data validation rules, and generate comprehensive reports, all within a user-friendly interface. This integration not only saves time but also ensures that your data remains accurate and reliable for any analysis or business decision.


Highlighting duplicates in Google Sheets is essential for maintaining the integrity of your data. Whether you choose to use Conditional Formatting, Google Sheets functions, or a Google Apps Script, each method provides a different level of control and efficiency. For those looking to expand their capabilities, offers a range of tools that enhance Google Sheets’ native functionalities, ensuring your data is not only clean but also powerful enough to drive insightful decisions.