Free Online CSV to Excel

1. Paste your CSV data into the input box.
2. Tick or untick whether the first row is a header so it becomes bold heading cells.
3. Click Download .xls to save the workbook.
4. Open the file in Excel; click Yes if it shows a format-mismatch prompt.
5. Re-apply number, currency, or date formatting in Excel if needed.

Excel's modern format, .xlsx, is a ZIP archive of XML parts — producing a valid one in the browser requires a packaging library. To stay dependency-free and fully client-side, this tool instead generates an .xls file using the HTML-table format that Excel has understood for two decades. You give it CSV; it parses the rows per RFC 4180, escapes the cell text, wraps it in a single HTML table, and saves the result with an Excel MIME type.

The upside is zero dependencies and instant, private conversion: your data never leaves the page. The trade-off is that the download is not a true binary workbook. Excel may show a one-time prompt warning that the file extension does not match its content; clicking Yes loads the worksheet normally. Numbers, text, and headers all carry across, though cell formatting such as currency or dates must be re-applied inside Excel.

This is ideal for handing a colleague a quick, editable spreadsheet from a CSV export. If you need a strict .xlsx — for an automated import pipeline or a tool that rejects the HTML format — open the .xls in Excel and re-save as .xlsx, or use a desktop converter.