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CSV Merger & Joiner

Join two CSV files on a shared key, or stack them, with inner, left and outer joins.

Merging two CSV files means either stacking their rows or joining them on a shared key. An inner join keeps only rows present in both, a left join keeps everything from the first file, and a full outer join keeps everything from both — the same semantics as SQL, and as a spreadsheet VLOOKUP.

Runs in your browser
Privacy
Runs entirely in your browser — nothing is uploaded
Cost
Free, unlimited, no sign-up

Frequently asked questions

Which join should I use?

Inner when you only want records that exist in both files. Left when the first file is your master list and the second adds detail — unmatched rows keep their data with blanks alongside. Full outer when you need to see everything, including what is missing from each side.

How to use the csv merger & joiner

  1. 1Enter or paste your first csv.
  2. 2Enter or paste your second csv.
  3. 3Enter or paste your join on column.
  4. 4Choose the join type.
  5. 5Choose the delimiter.
  6. 6Enter or paste your suffix for clashing columns.
  7. 7The result appears immediately — copy or download it.

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