convert

Merge CSV Files

Combine several CSV files into one, matching columns by header name even when they are in different orders.

Runs on your deviceCombines filesNew

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EPUB, CSV, TSV, JSON and other portable formats.

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Combine several CSV files into one, matching columns by header name even when they are in different orders.

Fine-tune

Optional — sensible defaults are already set.

About Merge CSV Files

This tool combines several CSV files into one. When the files have headers, columns are matched by name, so files with the same fields in a different order still line up, and fields that exist only in some files get their own column, left empty where missing. You can also add a column that records which file each row came from.

When it helps

  • Combining monthly or per-store sales exports into one file for analysis.
  • Joining the parts of a split CSV back into the original dataset.
  • Merging survey responses or sign-up lists collected in separate spreadsheets.

Tips

  • Header names must match exactly, including capitalization and spaces. "Email" and "email " become two separate columns, so tidy headers first if needed.
  • Turn on "Add a source-file column" to keep track of where each row came from. It adds a source_file column holding each file's name.
  • Turn off "First row is a header" only for files without headers. Rows are then stacked by position, so the columns must already be in the same order.
  • The merged file is written comma-separated, even if some inputs used tabs or semicolons.

Good to know

Quick answers about merge csv files in your browser.

No. Every row from every file is kept. Run the merged file through the duplicate remover afterwards if the inputs overlap.

No. Merging stacks rows from several files on top of each other. A join matches rows from two tables on a shared key and combines their columns side by side, which this tool doesn't do.

Yes. There is no sign-up, no watermark and no limit on how many files you process.

No. Files are read and processed locally in your browser, so they never leave your device.

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Part of the CSV Tools collection.