FileToastMerge CSV files
Combine CSV files with matching headers into a single CSV in your chosen order.
How to use Merge CSV files
- Choose files (CSV / TSV) from your device.
- Check your selected input before processing.
- Run the tool, inspect the result, and download your output.
What this tool does
Combine CSV files with matching headers into a single CSV in your chosen order. Headers must match exactly. A single header row is kept in the result.
Questions about Merge CSV files
Are my files uploaded?
This tool processes files in your browser. File contents are not uploaded to FileToast. Downloads stay wherever you save them.
Do the CSV headers need to match?
Yes. The input files must have matching headers so corresponding columns can be combined correctly.
How are the merged rows ordered?
Files are combined in the selected file order. Use the arrow buttons to change that order before merging.
What are the file and processing limits?
Up to 50 MB per file, 20 files and 100 MB total. Large or complex files can exceed your device’s or the converter’s capacity. Headers must match exactly. A single header row is kept in the result.