Drop several files. Columns are matched by header name, not by position, so exports with a different column order still line up. Nothing is uploaded.
Why matching by header matters. The usual way to merge exports is to paste one under another, which silently corrupts the data as soon as one file has its columns in a different order or is missing one. Here the header name decides where a value goes, and any column that was not present in every file is listed explicitly rather than quietly filled in.
| Different column order | Handled. Values follow their header, not their position. |
|---|---|
| Missing columns | With “keep every column”, rows from a file lacking that column are left blank for it, and the column is named in the summary. With “only columns present in all files”, it is dropped. |
| Different delimiters | Each file is sniffed separately, so a comma file and a semicolon file merge fine. The output uses the first file's delimiter. |
| BOM and line endings | Taken from the first file and written back, so Excel opens the result with accented and Turkish characters intact. |
| Header case | Region and region are treated as the same column; the first spelling seen is used in the output. |
| Size | Everything is held in memory. Comfortable up to a few tens of thousands of rows in total. |
What if the files have different columns? Columns are matched by header name. A column that exists in one file but not another is kept, and the rows that had no such column are left blank for it. The summary lists every column that was not present in all files, so nothing is merged silently.
What if the columns are in a different order? That is handled — matching is by header name, not by position. This is exactly the case that position-based merging gets wrong.
Can I tell which file each row came from? Yes. Leave the source column option on and a column holding the original file name is added as the first column.
Does the file leave my computer? No. There is no server behind this page. Files are read with the browser's File API and merged in the page. Once loaded, it keeps working with the network off.
Sheet Insights reads the merged result and profiles it — column types, missing values, outliers, an executive summary and one-click cleaning. Same rule as this page: everything runs in your browser, with no server behind it.
See what Sheet Insights does