Why Convert XLS to XLSX?

XLS is the older Excel binary format used through Excel 2003. XLSX, introduced in Excel 2007, is based on the Open XML standard and offers numerous advantages:

  • Smaller file size – XLSX files are compressed, saving disk space and speeding up sharing.
  • Better data recovery – The XML structure makes it easier to repair corrupted files.
  • Support for larger worksheets – Up to 1,048,576 rows vs. 65,536 in XLS.
  • New features – Conditional formatting, advanced charts, Power Pivot, and more.
  • Enhanced security – XLSX supports modern encryption algorithms.

Method 1: Using Microsoft Excel (Desktop)

If you have Excel 2007 or later, the conversion is built in:

  1. Open the XLS file in Excel.
  2. Click File > Save As (or Save a Copy in newer versions).
  3. Choose Excel Workbook (*.xlsx) from the dropdown.
  4. Select a destination folder and click Save.

Note: Some old macros or VBA projects may need adjustment if they rely on binary formats.

Method 2: Using Excel Online (Free)

No need to install software – use your browser:

  1. Go to Excel Online.
  2. Sign in with a Microsoft account (free).
  3. Upload the XLS file by clicking File > Open > Browse.
  4. Once opened, click File > Save As > Download a Copy.
  5. Choose Excel Workbook (*.xlsx) as the format.

Method 3: Using axztools.com – XLS to XLSX Converter

For a quick, secure, and no-registration conversion, use our online tool at axztools.com/xls-to-xlsx:

  1. Visit the tool page.
  2. Upload your XLS file (drag & drop or click).
  3. Click Convert – the process takes seconds.
  4. Download the converted XLSX file.

Our converter preserves all data, formulas, formatting, and even simple macros. It works on any device with a modern browser.

Common Questions About XLS to XLSX Conversion

Will I lose data after conversion?

No – modern converters maintain all content. However, if your XLS file uses Excel 2003-only features (e.g., certain chart types), they may be replaced with equivalents.

Can I convert multiple XLS files at once?

Yes! axztools offers batch conversion for premium users, or you can use Excel’s macro capabilities.

Is XLSX compatible with older Excel versions?

Excel 2000–2003 cannot open XLSX natively. Users must install the Microsoft Office Compatibility Pack or convert back to XLS if collaboration is required.

Conclusion

Upgrading from XLS to XLSX is a smart move for better performance, security, and feature access. Whether you use Excel desktop, online, or axztools, the process is straightforward. Start converting today and experience the modern Excel workflow.