List Compare
Two lists in, three lists out: in both, only in A, only in B.
About this tool
Paste list A and list B, one item per line. The tool shows three lists β in both, only in A, only in B β with counts, an overlap percentage and duplicate counts per list. Matching ignores case and surrounding spaces by default. Nothing is stored or sent.
The questions two lists answer
Comparing lists is a daily task that spreadsheets make awkward: which of last year's customers did not buy this year (only in A), which new sign-ups are not yet in the CRM (only in B), which keywords a competitor ranks for that you do not, which files on the backup are missing from the source. This tool is set arithmetic with sensible defaults β case-insensitive, trimmed, duplicates collapsed and counted β because email lists and SKUs arrive in every capitalisation. Order is preserved from the input so results stay recognisable. It is not a fuzzy matcher: 'J. Smith' and 'John Smith' are different items, and so are 'colour' and 'color'; normalise first with the text cleaner or the case converter, and clean addresses with the email list cleaner. For full documents rather than lists use the text diff.
Frequently asked questions
Does it handle large lists?
Tens of thousands of lines are instant; it runs in your browser's memory, so very large lists depend on your device.
Can I compare more than two lists?
Compare A with B, copy a result, then compare that with C. For joins across files with columns, use the CSV merger.
Does it see 'Apple' and 'apple' as the same?
Yes by default; untick 'ignore case' to make them different. Leading and trailing spaces are always ignored.
Is anything uploaded?
No. The lists are compared on your device and nothing is saved.