XLS to XLSXConvertisseur — Rapide et Gratuit

The XLS file format stores data in the XLS format. Converting to XLSX produces a spreadsheet file that stores cell values, formulas, formatting, and charts as zipped XML, the default format for Microsoft Excel 2007 and later. This conversion changes the file's encoding, compression method, and supported feature set. Cell values and structure are preserved; formulas are evaluated to their computed values in plain-text target formats. This makes XLSX the practical choice when the destination system requires it or when the target format offers better compatibility or compression. 1converter runs this conversion on the server: your file is uploaded encrypted over HTTPS, converted using trusted open-source libraries, and the output is held for 24 hours before automatic deletion.