CSV Merger (Combine CSV and Excel Files)

Monthly exports, one CSV per store, survey results downloaded in batches: combining them by copy and paste goes wrong as soon as the columns are in a different order or one file has an extra column. This tool merges CSV, TSV and Excel files by matching the header names (ignoring case and extra spaces), so each value lands in the right column. Keep every column or only the shared ones, add a column with the source file name, drop duplicate rows, and download the result as CSV or Excel.

How to use this tool

1. Choose the files (CSV, TSV, TXT, XLSX, XLS or ODS — the first sheet of a workbook is used), or paste tables separated by ---.
2. Match columns by header name (recommended) or by position.
3. Keep all columns or only those every file has.
4. Optionally add a source_file column and remove duplicate rows.
5. Pick CSV, TSV or Excel and download the merged file.

Formula

header = union (or intersection) of the column names · rows = every data row, each value moved to its column

Names are compared after trimming, collapsing spaces and ignoring case, so "Name", " name " and "NAME" are one column; the first spelling is kept. Rows from a file without some column get empty cells there. Duplicate rows are found by comparing every output cell. CSV output follows RFC 4180: values with commas, quotes or line breaks are quoted and lines end with CRLF. The UTF-8 BOM makes Excel recognise the encoding.

Example

Two exports — id,Name with Ada, and ID, name ,city with Lin from Seoul — merge into one table with the columns id, Name, city and 2 rows: 1,Ada, and 2,Lin,Seoul. With "Only columns every file has" the city column is dropped. Merging the same file twice gives 4 rows, or 2 with "Remove duplicate rows".