Find Duplicate Rows in CSV Files

To find duplicates in a CSV file online, open your file in Large CSV Viewer and use the column filter with the 'equals' operator to isolate a specific value, or use the global search bar to find all rows matching a term. Use Find & Replace (Ctrl+H) to standardize inconsistent duplicates. Free, no account needed.

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Find and review duplicate values in any CSV column online for free. Use column filters and search to locate and remove duplicates fast.

Duplicate data in CSV files causes broken imports, inflated reports, and incorrect analytics. Large CSV Viewer lets you quickly identify duplicate values in any column using column filters and search — no coding required.

Key features

  • Use column filters to isolate duplicate values by column
  • Global search across all columns for duplicate hunting
  • Find and replace to standardize inconsistent duplicates
  • Export deduplicated results as CSV, JSON, or Excel

How it works

  1. Upload your CSV. Open your data file in Large CSV Viewer. Any file size is supported.
  2. Search for duplicate values. Use the global search bar to find a specific value across all columns, or apply a column filter with the 'equals' operator to isolate exact duplicates.
  3. Fix and export. Use Find & Replace to standardize inconsistent values (e.g. 'New York' vs 'new york'), then export your cleaned dataset.

Ready to try it?

Free, instant — no account or install needed.

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Frequently asked questions

How do I find duplicate values in a CSV column?

Use the column filter with the 'equals' operator and enter the value you're looking for. Or use the global search bar to highlight all matching rows.

Can I remove duplicate rows automatically?

Automatic deduplication is on the roadmap. Currently, you can find duplicates using filters and delete or replace them with Find & Replace.

Can I find duplicates in large CSV files?

Yes. Filters and search run server-side using DuckDB, so duplicate detection works across millions of rows.

Can I fix duplicates using Find & Replace?

Yes. Find & Replace (Ctrl+H) lets you replace any value across all columns or a specific column — ideal for standardizing inconsistent duplicates.

Is this tool free?

Yes, completely free with no account or size limit.