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Merge Excel Files - Combine XLSX Workbooks

Upload multiple files and stack them into one large master file. Process locally in your browser with HappyCSV.

Preparing your private workspace…
How to use this tool

Quick start

Built for combining monthly exports, vendor files, or multiple csvs into one clean dataset.

Everything runs in your browser, so you can test the workflow with sample data when available before using production files.

Output: A single CSV with your source rows combined in order.

  1. 1Add the files in the order you want them combined.
  2. 2Review the file queue and adjust the file order.
  3. 3Process locally, then download the combined CSV.

How to Merge Files

  1. 1Add the files in the order you want them combined.
  2. 2Review the file queue and adjust the file order.
  3. 3Process locally, then download the combined CSV.

Why Use This Tool?

  • ✓Upload multiple files and stack them into one large master file.
  • ✓A single CSV with your source rows combined in order.
  • ✓Files are processed locally in this browser.
  • ✓Keep the source file and review the result before importing it elsewhere.

Frequently Asked Questions

What does this tool support?

A single CSV with your source rows combined in order.

What are the processing limits?

Up to 100 MB per CSV, 20 MB per complex document; 250,000 rows, 1,000 columns, 2 million cells, and 128 MB output. Jobs stop after two minutes. Large files may need splitting.

Are my files uploaded?

No. File processing stays in your browser. Files are not automatically saved for the next visit.

Can I process multiple files?

Yes. Add the files required for this operation and review their order before processing.