CSV Duplicate Row Remover
Remove duplicate rows from a CSV.
Clearing out repeats
Duplicate rows creep into data through merges, repeated exports and entry errors, and they distort any analysis. This removes duplicate rows from a CSV, leaving one of each, in your browser, so your data stays on your device.
Load a CSV to remove its duplicate rows.
Why duplicates matter, and what counts as one
Duplicate rows are one of the most common data-quality problems, and they genuinely corrupt results: counts come out too high, sums are inflated, and averages skewed, because the same record is counted more than once. Removing them is a standard and important cleaning step before any analysis. A key question is what counts as a duplicate — whether two rows must match in every column to be duplicates, or match only on certain key columns like an identifier. Exact-match deduplication removes rows identical across all fields, which is the safe default, while key-based deduplication catches records that are the same entity even if some other field differs. Deduplicating is essential after merging datasets, where the same records often appear in multiple sources, and for cleaning up data entered or exported more than once. Doing it in the browser keeps even sensitive records local, cleaned on your own device without uploading, which matters for the personal or confidential data that so often needs deduplicating.
Common questions
Why remove duplicate rows?
Because duplicates distort analysis — inflating counts and sums and skewing averages by counting the same record more than once. Removing them is a standard cleaning step.
What counts as a duplicate?
Usually rows identical across all columns, the safe default, though duplicates can also be defined by matching only certain key columns like an identifier.
Is my data uploaded?
No. The deduplication happens in your browser, so the data stays on your device.