Merge CSVs

Combine multiple CSV files into one

File A

File B

Merge Mode

Append rows as-is Concatenate File B below File A without column alignment Match columns by name Align columns by header name (case-insensitive)

Merged Output

Paste or upload two CSV files to merge...

More Options

CSV Format

Column separator Leave empty to auto-detect. Quote character Comment symbol Leave empty to disable comments.

Headers

File A has headers Treat the first row of File A as a header File B has headers Treat the first row of File B as a header

Keep headers from: File A File B

Input

Skip empty lines Ignore blank rows

How to Use This Tool

This tool merges two CSV files into a single combined file.

Load your files — Paste or upload your CSV files into File A and File B. Or click “Load sample” to try it out.
Choose a merge mode — Select “Match columns by name” to align columns or “Append rows as-is” to concatenate files directly.
Copy or save — Copy the merged CSV to your clipboard or save it as a file.

FAQ

4 questions

Does this tool upload my data?

No. It runs entirely in your browser using JavaScript. Your CSV data is never sent to a server.

What is the difference between the two merge modes?

'Match columns by name' aligns columns from both files by header name (case-insensitive) and fills missing values with blanks. 'Append rows as-is' simply concatenates File B below File A without column alignment.

What happens when files have different columns?

In 'Match columns by name' mode, all columns from both files are included. Columns unique to one file will have empty values for rows from the other file.

Can I choose which file's headers to keep?

Yes. When both files have headers, you can choose to keep File A's or File B's headers via a radio button in the options panel.

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