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CSV JOIN · INNER / LEFT JOIN

Join Two CSV Files by a Common Key

Select a shared column, such as a product code or employee ID, to combine related fields from two CSV files into one row. Both files stay in your browser.

Open this toolSpecifications & limits

CSV processing stays in your browserYour files are not uploaded to a server.

Join two CSV files by key

Combine rows that share a key such as Product Code or Employee ID.

How it works

  1. Choose the left CSV, then the right CSV.
  2. Select one key per file and choose INNER or LEFT JOIN.
  3. Review the preview and row counts, then download.

Before you start

  • Limits: 50 MiB total and one key per file. Blank keys do not match.
  • Repeated keys on both sides can increase output rows; deduplicate first if needed.
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