Find exact duplicate CSV rows locally.

Choose a small comma-delimited CSV or paste text. The checker counts repeated data rows and reports their record numbers without uploading or changing the file.

What counts as a duplicate? Every parsed column must match exactly. Spaces, letter case and numeric formatting remain significant: 001 differs from 1, and Ada differs from Ada . The first row is treated as the header. Record numbers refer to data records, so multiline quoted fields do not change the numbering.

Limits: 5 MB, 10,000 data records, 100 columns and comma-delimited CSV only. This checker does not remove rows, write an output file, infer business duplicate keys or prove that two different customer records represent the same person.