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CSV Merge & Join

Combine two CSV datasets using a matching column. Ideal for enriching exports with metadata, syncing CRM lists, or joining analytics tables.

Free to use, no watermarks, runs in your browser—nothing uploads to our servers

CSV samples

Loaded sample: Default sample

CSV data

Supports header rows, quoted values, and multi-line fields.

Secondary CSV data (to join)

Delimiter

Use first row as headers

Jump to helper sections

What type of join does this tool perform?

It performs a left join: every row from the primary CSV is kept, and matching data from the secondary CSV is appended. Unmatched rows are padded with empty values.

Do my CSVs need matching column names?

No, you can choose different join columns for each CSV. Simply pick the column that shares the same IDs or keys between the datasets.

Can I download the merged result?

Yes. After processing, use the download button to save the merged CSV for further analysis.

Report a bug

If this tool misbehaves, share a quick summary so we can investigate. We include the tool URL automatically—no need to copy and paste.