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ConvertBox

CSV ↔ Excel Converter

Convert between CSV and Excel (.xlsx) formats instantly in your browser.

📄

Upload CSV File

Select a CSV file to convert to Excel

Max file size: 50MB

or drag and drop · press Enter to browse

How to Use

  1. Choose conversion direction: CSV → Excel or Excel → CSV
  2. Upload your file by clicking or dragging
  3. Preview the converted data
  4. Download the converted file
  5. Copy the formatted or generated result directly to your clipboard.
  6. Use the result in your application, configuration, or documentation safely.

All processing is done in your browser, and files are never sent to a server.

Frequently Asked Questions

No, all conversion happens in your browser. Files never leave your device.
Both .xlsx and .xls formats are supported for input. Output is always .xlsx.
Files up to 50MB are supported. Larger files may take longer to process.
Basic data and structure are preserved. Complex Excel formatting (colors, formulas) may not be retained.
When converting Excel to CSV, only the first sheet is converted. For multi-sheet files, use the Excel Viewer tool.
Yes, the converter works on all modern browsers including mobile devices.
No. All tools on ConvertBox are 100% free. We do not insert watermarks, limit features, or require any registration or payment.
Yes. Once the page and its local library dependencies are loaded in your browser, the conversion logic runs completely offline without needing an active internet connection.

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