Tiny Toolkit

CSV Deduplicator

Upload a CSV or paste data and remove duplicate rows based on one or more selected columns. The result shows how many duplicates were found and removed, with the clean data ready to copy or download. Useful for deduplicating contact lists, order exports, CRM data, and any tabular dataset that has accumulated repeated entries.

All processing happens in your browser. No data is sent to any server.

Frequently Asked Questions

How does the deduplication work?
After uploading or pasting your CSV, check the columns you want to use as the deduplication key. Two rows are considered duplicates when all selected column values match. Only the first occurrence of each unique combination is kept.
Can I deduplicate by just one column instead of all columns?
Yes. Uncheck all columns except the one you want to use as the key. The tool will remove any rows where that single column value has already appeared.
Is the header row included in deduplication?
No. The first row is always treated as a header and is preserved as-is. Only the data rows below the header are compared and deduplicated.
Is the comparison case-sensitive?
Yes, the comparison is case-sensitive by default. Rows with the same values in different cases (for example "Alice" and "alice") are treated as distinct.

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