Which formats can I convert between?

Excel (.xlsx/.xls) to CSV, TSV, semicolon-CSV or JSON — and CSV/TSV back to a styled .xlsx with bold frozen headers.

Does it handle multiple sheets?

Yes — pick any sheet from a workbook, or convert every sheet at once (one file each, or one combined workbook).

Is my spreadsheet uploaded?

No — parsing happens in a background thread of your browser. Financial data never leaves your device.

What about legacy encodings?

Files that aren't UTF-8 (older exports) can be re-read as Windows-1252 with one click.

CSV to Excel Converter Free — In Your Browser, No Upload

A CSV turned into a real .xlsx workbook with a styled header row, so it opens in Excel or Sheets as a spreadsheet rather than a wall of unformatted text.