Merge CSV files into one

How to merge CSV files

1. Add your files. Choose several at once, and add more later if you need to. Each sheet of an Excel workbook is added as its own table.
2. Arrange them with the ↑ buttons if the order matters. Rows are added in the order of the list.
3. Choose the options: line up columns by name or by position, add a source-file column, remove duplicate rows.
4. Download the merged CSV or Excel file.

Matching columns by name

With by column name (the default), a column called Email in one file and email in another end up in the same column, even if one file has it first and the other last. Columns that only some files have are added at the end, and rows from files without them are left blank there. Nothing is dropped.

With by position, the first column of every file goes into the first column of the result, and so on. Use it when the files have no header row, or when the same columns have different names.

Source column and duplicates

• Source file adds a first column showing the file (and sheet) each row came from. This helps if you later need to trace or filter rows by file.
• Remove duplicate rows keeps the first copy and removes later rows that are identical in every column. Spaces at the start or end of a value are ignored. The number of rows removed is shown before you download.

Mixed separators and text formats

The separator (comma, semicolon, tab or pipe) and the text format (UTF-8, UTF-16 or Windows-1252) are detected separately for each file, so files exported from different systems can be merged. The result is a standard UTF-8 CSV file, or an Excel workbook.

Doing it in Excel instead

Excel for Microsoft 365 on Windows can also combine files kept in one folder with Power Query: Data → Get Data → From File → From Folder, choose the folder, then Combine & Transform Data. This suits a job you repeat every month with files of the same layout. For a one-off merge, or files whose columns or separators differ, choosing the files here takes fewer steps.