How to combine multiple CSV or Excel files into one
Merge monthly exports or branch reports into one sheet, with columns lined up by name even when the files differ.
Updated 2 October 2026
Monthly exports, one file per branch, or reports from different team members: combining them by copying and pasting is slow, and columns in a different order cause mistakes.
How to merge
- Open Merge CSV / Excel and select all the CSV and Excel files.
- Choose whether to save as CSV, Excel or TSV.
- Optionally tick "Add a column showing which file each row came from".
- Download the combined file.
When the columns differ
Columns are matched by their header name, not their position. If one file has an extra column, it is kept, and rows from the other files get an empty value there. Name columns consistently (for example always email, not sometimes E-mail) for the best result.
After merging
- Remove repeated customers with Remove duplicates.
- Tidy spacing and capitalisation with Clean CSV / Excel.
- Compare the result with another list using Compare two files.
The first sheet of each Excel file is used. Up to 500,000 rows can be combined.