Compare and diff two CSV files. Fast, secure, and completely free. All processing happens in your browser — no data is sent to any server.
CSV Compare aligns two CSV files by their header columns (rather than by raw line position) and reports which rows were added, removed, or had specific cell values changed. Because CSV rows can be reordered by a sort, an export tool, or a spreadsheet save without the underlying data actually changing, a plain line-by-line text diff produces a huge and mostly meaningless changeset. This tool instead matches rows using a key column you choose (like an ID), so it can tell you 'row with ID 482 changed its email column' instead of just 'line 17 is different.'
Comparing two exports of the same dataset — a nightly database export, two versions of a spreadsheet, or before/after a data migration — almost always involves rows that got reordered or re-sorted along the way, which makes a plain text or line diff nearly useless. Matching by a key column instead answers the question you actually care about: which specific records changed, which were added, which disappeared, and in which exact fields — without wading through noise caused by row order alone.
As long as you select a key column present in both files, rows are matched by that key rather than by position, so reordering alone won't produce false differences.
Yes, columns are matched by header name, not position, so a reordered set of columns with the same headers compares correctly.
Yes, common delimiters are automatically detected, or you can specify the delimiter manually if auto-detection doesn't match your file's format.
It's reported as either an added or a removed row, depending on which file it's missing from, rather than being incorrectly matched against an unrelated row.
There's no hard limit enforced, but very large files (hundreds of thousands of rows) may take noticeably longer to process since comparison happens in your browser.