Online Tool Store
CSV Merger
Combine CSV files with matching headers into one download. Check column order, preview the first 20 data rows, and merge locally in your browser.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
How it works
- Choose at least two non-empty CSV files with the same headers in the same order.
- Click Merge CSVs to check headers and append the data beneath one header row.
- Review the first 20 data rows, then download the complete merged.csv file.
FAQ
Do CSV columns need to be in the same order?
Yes. Header names must match in the same order. Leading and trailing spaces are ignored during the header comparison; mismatched files are listed in an error.
Does CSV Merger remove duplicate rows?
No. It appends the parsed data rows from every file without deduplication.
Does the 20-row preview limit the download?
No. The preview shows the first 20 data rows, while merged.csv contains the full merged output.
Are my CSV files uploaded?
No. File reading, CSV parsing, and merging happen in your browser.
How we compare
| Feature | Online Tool Store | Copy-pasting between spreadsheets | Command-line concatenation |
|---|---|---|---|
| No terminal or spreadsheet app needed | ✓ | ✓ | ✗ |
| Checks headers match before merging | ✓ | ✗ | ✗ |
Copy-pasting rows between spreadsheets is slow and error-prone for more than a couple of files. CSV Merger checks columns match, then combines everything in one click.