CSV Deduplicator
Drop a CSV file to find and remove duplicate rows. Choose which columns to compare, what to keep, and download the cleaned result. Your data never leaves your browser.
Drop a CSV or TSV file here, or click to select.
CSV, TSV · Max 2 GB
How to use CSV Deduplicator
- 1
Drop your CSV
Drag a .csv or .tsv file onto the dropzone.
- 2
Pick comparison columns
Use the column picker to choose which columns define a duplicate. By default, every column is compared.
- 3
Choose what to keep
First keeps the earliest occurrence, Last keeps the most recent, None drops every duplicated row entirely.
- 4
Download the deduped CSV
Compare the before / after row counts, preview the result, then click Download.
Frequently asked questions
- Does this tool upload my CSV?
- No. Every parse, transform, and download runs entirely in your browser using JavaScript and Web Workers. The file never leaves your device — there is no upload endpoint and no server-side processing.
- Is the comparison case-sensitive?
- Yes — values are compared exactly. If you want case-insensitive deduplication, normalize the casing first with CSV Filter & Transform or a small spreadsheet step.
- What does the None keep mode do?
- It removes every row that has any duplicate. Use it when a duplicate indicates bad data and you'd rather drop the whole group than guess which row is canonical.
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