XLS to XLSX Converter
Upgrade your spreadsheets. Convert old .xls files to the modern .xlsx format for full compatibility with newer Excel versions.
Why Convert XLS to XLSX?
The .xls format, used until Excel 2003, is outdated and has limitations on rows and columns. Converting to .xlsx uses the modern XML-based format, which results in smaller file sizes, better data recovery, and support for over a million rows.
Upgrading ensures your files remain compatible with Office 365, Google Sheets, and other modern data tools.
How to Convert XLS to XLSX
- Upload your legacy .xls workbook.
- The tool converts the structure to modern XML .xlsx.
- Click 'Convert' to finish.
- Download your upgraded Excel file.
Key Features of MiConvert XLS to XLSX
- Upgrade legacy Excel files
- Reduced file size
- Preserves data and formatting
- Supports multi-sheet workbooks
- Secure conversion
- Free to use
Frequently Asked Questions
Will I lose my formulas?
Most standard formulas are preserved and transferred to the new format seamlessly.
Are macros kept?
No, this conversion produces a standard .xlsx file which does not support macros. If you need macros, you would typically convert to .xlsm, which this specific tool does not output.
Is the new file smaller?
Yes, .xlsx is a compressed format, so your spreadsheets will take up less storage space.
Can I open it in old Excel?
Excel 2007 and newer open .xlsx natively. Older versions may need a compatibility pack.