CSV Deduplicate
Drop duplicate rows from a CSV — either by full-row match or by specific key columns. Choose whether the first or last duplicate wins.
About CSV Deduplicate
CSV Deduplicate removes duplicate rows from a CSV, either by matching the entire row or by specific key columns you choose. You control which copy survives — first or last occurrence wins — which matters when later rows hold the freshest values. It processes the file in your browser, so even a customer or sales export never leaves your machine.
- Category
- edit
- Input
- Accepts: text/csv or text/plain.
- Output
- Outputs: text/csv (multiple).
- Cost
- Free, runs in your browser
- Memory
- low
Common uses
- Collapse a mailing list to one row per email address, keeping the most recent entry
- Remove exact duplicate rows that crept in after concatenating several CSV exports
- Dedupe a product feed on SKU so each item appears once even if it was listed twice
- Clean a survey export where respondents submitted twice, keeping their last submission
- Reduce a transaction log to unique entries by a composite key of date and order ID
Frequently asked questions
Can I dedupe on just one column?
Yes. Choose one or more key columns and rows are considered duplicates when those columns match, even if other columns differ. Or match on the full row.
Which duplicate is kept?
You decide — first occurrence or last occurrence wins. Pick last when later rows carry updated values you want to preserve.
Is my CSV uploaded?
No. Deduplication runs in your browser, so the data — including any personal or commercial records — stays on your device.
What's the output format?
A CSV with duplicate rows removed, preserving the header and column order of your input.
Does it change the order of the remaining rows?
Surviving rows keep their original relative order; only duplicates are dropped according to your first/last setting.
Keywords
- csv
- deduplicate
- dedup
- unique
- distinct
- rows