How to merge multiple Excel files into one
Combine dozens of .xlsx, .xls or .csv workbooks into a single file — by stacking rows or by keeping one sheet per source — without copy-pasting a thing.
Before you start
You need the Little Beaver Table Merger, a Windows app from the Microsoft Store. It runs fully offline, so your data never leaves the machine.
Put the workbooks you want to combine into one folder. They can be a mix of .xlsx, .xls and .csv. The column order does not have to match — you decide how columns are aligned in the next step.
Stack rows into one sheet
Open the app and add your files. Pick a key column (for example a shared ID or date) so rows line up correctly, or leave it empty to simply append everything in order.
Choose the 'Append rows' mode. The app reads each file, maps its columns to the output, and writes one combined table.
This is the right mode when every file describes the same kind of record — monthly exports of the same report, for instance.
Keep one sheet per file
When the workbooks are not comparable — different layouts, different purposes — switch to 'One sheet per file'.
Each source becomes its own tab in the output workbook, named after the original file, so nothing gets mixed up.
Export and verify
Click Export and choose .xlsx or .csv. Open the result and check the row counts against your sources.
If a column looked wrong, go back, remap it, and re-export. Nothing is uploaded and no account is required.
