Google Sheets Add-on to combine your data from different sheets to one. Merge Sheets will assist and automate your action: you can combine sheets by stacking rows or joining data from different sheets. STACK means combining your selected sheets in a new one, one after the other. If the data has headers, only the first sheet's header line is kept. JOIN involves two tables linked by a common field called a Lookup Key. You combine data from the first table with columns from the second table where the lookup key in the first table matches the index key in the second table. Merge Sheets will try to automatically detect the best match.