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CSV Duplicate Row Remover
Remove duplicate rows from a CSV file in seconds. Compare entire rows or only the columns you pick (such as Email), ignore differences in case and spacing, and keep the first or last copy. You see exactly which rows were removed before you download the cleaned file.
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How to use the CSV Duplicate Row Remover
- Open your CSV file or paste the data. The delimiter is detected automatically.
- Choose what counts as a duplicate: the whole row, or only selected columns such as Email or ID.
- Set the matching rules: ignore case and extra spaces, and decide whether to keep the first or the last copy.
- Review the result: the counters show rows kept and removed; the Removed rows tab lists every dropped row.
- Download the cleaned CSV (and the removed rows if you want a record of them).
Whole-row vs key-column deduplication
| Rows | All columns | Selected: Email |
|---|---|---|
Ben,[email protected],LeedsBen,[email protected],Leeds | Second row removed (identical) | Second row removed |
Chen,[email protected],TorontoChen,[email protected],Vancouver | Both kept (City differs) | Second row removed (same email) |
Ana,[email protected]ana,[email protected] | Removed only with Ignore case + Ignore spaces | Removed only with Ignore case + Ignore spaces |
Tips for a clean dataset
- Pick a real key. For contact lists the email address is usually the best duplicate key; for orders use the order ID; for products the SKU.
- Keep the newest record. If your export is sorted oldest to newest, choose Keep the last row so updated details win.
- Audit before deleting. Download the removed rows as a backup and add the count column to see which records were repeated most.
- Combining several exports? Merge them with the CSV Merger first, then deduplicate here. To see what changed between two versions of a file, use the CSV Diff Checker.
Frequently asked questions
How do I remove duplicate rows from a CSV file?
Open the CSV here; with Find duplicates by set to All columns, every row that exactly repeats an earlier row is removed immediately. Click Download cleaned CSV to save the file without duplicates. The header row is always kept.
Can I remove duplicates based on one column, like email?
Yes. Choose Selected columns only and tick the Email column (or any combination of columns). Rows are then treated as duplicates when those columns match, even if other columns differ, and the first (or last) row for each email is kept.
Are '[email protected]' and '[email protected] ' treated as the same?
With Ignore upper/lower case and Ignore extra spaces ticked (the default), yes: values are compared in lower case with leading, trailing and repeated spaces removed. The original values are kept unchanged in the output.
Which copy is kept: the first or the last?
By default the first occurrence is kept and later copies are removed, so the original order is preserved. Choose Keep the last row to keep the most recent entry instead, or Remove all copies to drop every value that appears more than once.
Can I see which rows were removed?
Yes. Open the Removed rows tab: each removed row shows its original row number and the row it duplicated. You can download these rows as a separate CSV.
Does it work with large CSV files?
Yes. Duplicate detection uses a hash map, so hundreds of thousands of rows are processed in a second or two on a typical computer. Very large files are not shown in the text box but are processed in full.
Is my CSV uploaded?
No. The file is read and processed by JavaScript in your browser. Nothing is sent to any server.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.
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