How to convert Excel XLS to XLSX
- Add your .xls files.
- Excel (.xlsx) is preselected — start the conversion.
- Download your .xlsx workbooks.
.xls is the format of Excel 97 to 2003. Many businesses and accountants still have plenty of them: old payroll sheets, customer lists, stock trackers and reports exported by business software. The format has real limits — at most 65,536 rows and 256 columns per sheet — and the files are larger.
.xlsx, used since Excel 2007, handles over a million rows (1,048,576) and 16,384 columns, compresses the data and is better supported by Google Sheets, Power BI, LibreOffice and mobile apps. Converting your .xls files lets you keep adding data without hitting a wall, and gets rid of Excel's “Compatibility Mode”.
The conversion runs with LibreOffice: every sheet, formula, number and date format, merged cell and style is carried over. VBA macros cannot be stored in an .xlsx file. Your files are deleted after 30 minutes.
Tip: after converting, open the workbook and check one or two key totals — formulas are recalculated in the new file, so any cell that showed an error before will still show it. Charts, cell comments, data validation lists and freeze panes are carried over. If your .xls was password-protected against opening, remove the password in Excel first, otherwise the file cannot be read.
Frequently asked questions
What is the difference between XLS and XLSX?
XLS is the old binary format of Excel 97-2003, limited to 65,536 rows per sheet. XLSX is the XML format of Excel 2007 and later — smaller and able to hold 1,048,576 rows.
Are my formulas kept?
Yes, formulas, sheets, number formats and styling all come through in the .xlsx workbook.
What about macros?
An .xlsx file cannot contain macros. If your .xls has some, save it as .xlsm in Excel to keep them.
Can I convert several workbooks?
Yes, up to 50 .xls files at once, 300 MB maximum each.
Is it free?
Yes, completely free with no account to create.