Merge CSV files into one
Twelve monthly exports, one file per branch, a folder that grows every quarter. This stacks them into one file with a single header row at the top. If the columns sit in a different order in each file, it matches them up by their headings.
Your file stays on this computer. There’s no upload button here, because there’s nowhere to send it. This tool runs inside the page you opened — like a calculator on a web page, it keeps working once it has loaded. How this works, and how to check it →
How to use it
- Choose two or more CSV files. They're merged in the order listed.
- Decide whether to match up columns by their heading — useful when the files list their columns in a different order.
- Click Merge and download the combined file.
Questions
Is my file uploaded anywhere?
No. The whole tool is inside this page, so the work happens on your computer. There is no server to send it to. If you'd rather check than take our word for it: use the tool once, on a sample file, with the settings you want. Then turn off your wi-fi and do exactly the same thing again in that tab, without reloading. It still works, because everything it needs is already here.
What if my files have different columns?
When columns are matched by their heading, the result has every column found in any file, and a file missing one gets an empty cell there. With it off, rows are stacked in position order and the first file's header row is used. That's faster, and only right if every file has the same columns in the same order.
Can I control the order files are merged in?
Yes. Files merge top to bottom in the order shown after you add them. Remove one with the × and add it again to move it to the end.
How do I merge CSV files on a Mac?
The same way as anywhere else — add the files here and click Merge. The Terminal command cat *.csv > merged.csv works, but it copies every file's header row into the middle of the result. This page keeps one header row, and it runs the same on a Mac, on Windows or on anything with a browser.
How do I combine CSV files in Excel?
Excel's route is Data → Get Data → From Folder, then Combine in Power Query. It's several screens, it needs every file to share exactly the same columns, and it's Windows-first. Adding the files here and clicking Merge is the same result in one step — and when columns are matched by their heading, it tolerates files whose columns are in a different order.