Merge two CSV files by matching columns

Merge two CSV files by matching a key column, even if its name differs from one file to another (e.g., “id” and “client_id”).

Example:

How it works

Do you have two CSV exports about the same subject (customers, orders, products) but with different column names? Specify the key column for each file (e.g., “id” in one and “client_id” in the other), choose the merge type, and the columns from both files are combined into a single row based on key matching.

What is the difference between the three merge types?

“Matches only” keeps only rows whose key exists in both files. “All of the 1st CSV” keeps all rows from the first file, filling in with empty cells when there is no match in the second. “Full outer” keeps all rows from both files, including those without any match.

What happens if a column exists in both files?

If a column name (other than the key) is present in both files, the one from the second file is renamed with the “_2” suffix in the result, to avoid any naming conflict.

100% local processing: the merge happens entirely in your browser; your two CSV files are never sent to a server.