How to remove duplicate rows in Google Sheets without losing the original CSV
A review-first Google Sheets workflow for exact duplicates, near-duplicates, and exporting a cleaned CSV without overwriting the source file.
Before you work through this by hand: you can check your own CSV free and see which of these problems your file actually has — duplicate rows, near-duplicates, broken quoting, encoding damage. It runs in your browser tab, nothing is uploaded, and there's no signup or email.
1. Import a copy, not the only export
Keep the downloaded CSV unchanged, then open a working copy in Google Sheets. Record the original row count and leave the header row at the top. This makes it possible to notice if an import or cleanup step silently dropped data.
2. Remove exact duplicates
- Select the full table, including every column that should be preserved.
- Choose Data → Data cleanup → Remove duplicates.
- Keep all columns selected when a whole row must match exactly, or select only the identity columns when the business rule is explicitly key-based.
- Review the reported rows removed and compare the final row count with your notes.
3. Review near-duplicates separately
Google Sheets removes exact matches, but it will not reliably identify the same contact with different capitalization, extra spaces, a typo, or a changed phone format. Normalize comparison keys in helper columns, then filter and review candidate groups instead of deleting similar-looking rows automatically. Two rows with the same email can still disagree on consent, owner, or address and need a human decision.
4. Export and verify the cleaned copy
Use File → Download → Comma-separated values (.csv), reopen the downloaded file with a CSV-aware parser, and spot-check quoted commas, non-ASCII text, headers, and row counts. Keep the original export until the destination import succeeds.
For a private local check before opening a spreadsheet, CSV Repair & Deduper flags exact and near-duplicate candidates in your browser, keeps original values visible, and exports a separate reviewed CSV. Check your CSV free before deciding whether the $19 workflow fits.
See also: our general duplicate-removal guide, deduplication vs. manual review, and backup/versioning guide.
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