CSV MERGER · UNION ALL
Merge Multiple CSV Files into One
Stack CSV files with the same columns—such as daily, monthly, or store exports—in the order selected. Headers are checked first, and the result can be saved only when input and output row counts match. Everything is processed in your browser.
CSV processing stays in your browser
Your files are not uploaded to a server.
File selection
Select 2–20 files, up to 50 MB in total. Files are merged from top to bottom in the selected order.
Drop multiple CSV files here
or
Up to 20 CSV files, 50 MB total
How it works
Example: merge daily sales CSV files into one file
How it works
Example: merge daily sales CSV files into one file
CSV files with the same columns are appended from top to bottom in the selected order. The header is kept only from the first file.
Input example (2 files)
| File | Date | Store | Quantity |
|---|---|---|---|
| July 1.csv | 7/1 | New York | 3 |
| July 2.csv | 7/2 | Chicago | 1 |
After merging
| Date | Store | Quantity |
|---|---|---|
| 7/1 | New York | 3 |
| 7/2 | Chicago | 1 |
Merging vertically is equivalent to UNION ALL. It is useful for combining monthly, daily, or store CSV files that have the same columns.