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Find and Remove Duplicate Rows in CSV

Upload any CSV or Excel file and instantly see every duplicate row with its exact row number. Remove all duplicates in one click and download the cleaned file no code, no Excel formulas, no signup.

🔍 Exact row numbers shown
⚡ Results in seconds
⬇️ Download cleaned CSV/Excel
🔒 No upload to server
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CSV & Excel Data Analyzer

Find duplicates, nulls & errors · Clean & export · Auto dashboard

∞ All Rows🔒 No Upload⚡ Free
🔁 Duplicates⬜ Nulls⚡ Type Check📊 Stats📉 Outliers💡 Insights🔧 Clean📈 Dashboard⬇️ Export📡 API
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Drop your data file here

or click to browse CSV, Excel (.xlsx / .xls) or JSON

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Free CSV and Excel Data Analyzer Find Duplicates, Nulls and Errors Instantly

Upload any CSV or Excel file to instantly find duplicate rows, null values, type mismatches and data quality issues. The Clean Data tab lets you remove duplicates, fill nulls and standardize headers in one click, then download the cleaned file. The Dashboard tab auto-generates charts from your data. No Python, no SQL, no formulas required.

How do I find and remove duplicate rows in CSV?
Upload your file, then go to the Clean Data tab. Click "Remove Duplicate Rows" to deduplicate instantly. The row count updates and you can download the cleaned file as CSV, Excel or JSON.
Can I fill null values instead of deleting rows?
Yes. In the Clean Data tab, choose "Fill Nulls" with options to fill with 0, with the column mean, or with an empty string. This lets you keep all rows while fixing missing values.
What does the Dashboard tab show?
The Dashboard tab auto-generates bar charts for numeric columns showing value distribution, and donut charts for categorical columns showing the most frequent values. It gives you an instant visual overview without any configuration.
Does this tool process all rows?
Yes. There is no row limit. All rows are processed in your browser. Your files never leave your device.

Why Duplicate Rows Are a Serious Data Problem

Duplicate rows are one of the most common data quality issues, and one of the most damaging. Unlike missing values which are visible, duplicates are invisible until you look for them. A dataset with 5% duplicate rows will produce a revenue total that is 5% too high, a customer count that is 5% too high, and any rate or percentage that is calculated from those numbers will also be wrong.

The most common cause is data being appended to a CSV multiple times a scheduled export that ran twice, a manual copy-paste from two overlapping date ranges, or a merge of two tables that shared records. Another common source is data imported from multiple systems where the same customer or transaction exists in both.

Before loading any CSV into a database, Power BI, Tableau or any analysis tool, checking for and removing duplicate rows is one of the first steps every data professional takes. This tool does that check instantly, without requiring any technical knowledge or software installation.

How to Find and Remove Duplicate Rows Step by Step

1
Upload Your CSV or Excel File

Click the upload area above or drag your file onto it. CSV, Excel (.xlsx and .xls) and JSON files are all supported. Your file is read entirely in your browser nothing is sent to any server.

2
Check the Issues Tab

After analysis completes, click the Issues tab. The Duplicate Rows section shows the exact count of duplicate rows and lists every duplicate with its row number and the row it copied.

3
Preview the Duplicates

Click "Show preview" to see a table of the first five duplicate pairs. This helps you verify the tool is detecting the right rows before you remove them.

4
Remove Duplicates with One Click

Go to the Clean Data tab and click "Remove Duplicate Rows". The row count updates immediately to show the new total.

5
Download the Cleaned File

Click CSV, XLSX or JSON to download your deduplicated file. The filename is "data-export" so you can easily find it.

Frequently Asked Questions

How does the tool decide if two rows are duplicates?
Two rows are considered duplicates if every column value matches. The comparison is case-insensitive and ignores leading and trailing whitespace. So "New York" and "new york " would match. Values like 100 and 100.0 would not match unless they are stored as identical strings.
What if I only want to check specific columns for duplicates?
This tool currently checks all columns for exact row-level duplicates. If you need to deduplicate based on a subset of columns, the best approach is to use the Download button to export the data to CSV, then use the CSV to SQL tool on TOOLBeans to write a SELECT DISTINCT query on just those columns.
How many rows can the tool handle?
There is no row limit. All rows in your file are processed. For very large files above several hundred thousand rows, processing may take a few seconds depending on your device.
Can I undo the duplicate removal?
Yes. In the Clean Data tab there is a Reset All button that restores your original data. The tool never modifies your original file on disk it only works with the in-memory copy.
Does this tool also detect duplicate columns?
Yes. In addition to duplicate rows, the tool detects duplicate columns columns that have identical values across every row. These are shown separately in the Issues tab and can also be removed from the Clean Data tab.

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