How to convert XLS to XLSX
- Choose or drop your XLS files. You can add several at once.
- Check that “To” is set to XLSX.
- Press “Convert to XLSX” and download the results — or all of them as one ZIP.
XLS vs XLSX
XLS — Excel 97–2003 workbook. XLS is the older binary Excel format, used before 2007. Modern Excel still opens it, but many newer tools and libraries only read XLSX.
XLSX — Excel workbook. XLSX is the Microsoft Excel format. A workbook can hold several sheets with formatting and formulas, and it opens in Google Sheets, Numbers and LibreOffice.
Convert XLS to XLSX when you need a file for spreadsheets people will open and edit. XLS is better suited to very old versions of Excel.
FAQ
5Are my files uploaded anywhere?
No. The conversion runs in your browser using your own device’s processor. Your files are never sent to a server, so nobody — including us — can see them. You can even disconnect from the internet after the page loads.
Will I lose quality?
Cell values and sheets are carried over to XLSX. Advanced Excel features such as macros, pivot tables and some formatting may not survive the conversion.
Is there a file size or daily limit?
No limits, and no sign-up. Because nothing is uploaded, we don’t pay for your conversions and have no reason to cap them. Very large files are limited only by your device’s memory.
Can I convert many XLS files at once?
Yes. Add as many files as you like; each is converted to XLSX, and “Download all” saves them together as a ZIP.
Does it work on iPhone and Android?
Yes. It works in any modern browser — Safari, Chrome, Firefox or Edge — on phones, tablets and computers. Older or low-memory phones may be slower with very large files.