How to Convert XLS to XLSX
Learn how to convert XLS to XLSX, why the newer format is useful, and what to check after upgrading the file.
How to Convert XLS to XLSX (Quick Answer)
You can convert XLS to XLSX by opening the older spreadsheet in Excel or a compatible app and saving it in the newer Excel workbook format.
The usual steps are:
- Open the XLS file
- Check for compatibility warnings
- Save as XLSX
- Reopen the new file
- Confirm the formulas and formatting still work
The newer XLSX format is usually more flexible and widely supported.
Why Convert to XLSX?
XLSX is the modern Excel format.
It is often preferred because it can:
- Support newer Excel features
- Handle larger workbooks
- Work better with modern tools
- Reduce some compatibility issues
If you still need the old format for legacy reasons, keep a backup copy.
Watch for Compatibility Issues
Older XLS files may contain features that need attention during conversion.
Check for:
- Macros
- Legacy formulas
- Old chart formatting
- External links
- Password protection
If the workbook relies on old behavior, the conversion may require a quick cleanup.
Review the Converted Workbook
After saving as XLSX, reopen the file and inspect it.
Make sure:
- Formulas still calculate correctly
- Sheets are in the right order
- Charts still display properly
- Cell formatting is intact
- File size and performance look normal
That final review helps catch problems before the file is shared.
Best Practice Summary
If you want the short version:
- Open the XLS file in Excel
- Save it as XLSX
- Check for compatibility warnings
- Review formulas and formatting after conversion
- Keep the original XLS as a backup if needed
That is the simplest way to convert XLS to XLSX.
FAQ
Will macros still work in XLSX?
Only if you save as a macro-enabled format like XLSM. Plain XLSX does not keep VBA macros.
Do I lose data during conversion?
Usually not, but formulas, formatting, or legacy features may need review.
Why does Excel warn about compatibility?
The workbook may use features that do not map perfectly into the newer format.
Should I delete the old XLS file?
Not until you are sure the XLSX copy works correctly.