Free Online Converter
Convert XLS to XLSX
Free online Legacy Excel Spreadsheet to Microsoft Excel Spreadsheet converter. Fast, secure processing directly in your browser.
How to Convert XLS to XLSX
- Click or drag your XLS file into the upload area above
- Wait for the file to be loaded (happens instantly in your browser)
- Click the "Convert File" button
- Your processed XLSX file will automatically download
Why Convert XLS to XLSX?
Convert between spreadsheet formats easily. Export Excel files to CSV for database imports, convert to JSON for web applications, or create Excel files from your data. All processing happens in your browser.
Key Features
100% FreeNo subscription, no hidden fees, no limits
Privacy FirstFiles never leave your device
Fast ProcessingInstant browser-based conversion
No InstallationWorks directly in your browser
High QualityMaintains quality during conversion
SecureClient-side processing only
About XLS and XLSX Formats
XLS (Legacy Excel Spreadsheet)
XLS is the legacy Microsoft Excel format used before 2007. Limited to 65,536 rows compared to XLSX.
XLSX (Microsoft Excel Spreadsheet)
XLSX is the modern Microsoft Excel format supporting multiple sheets, formulas, charts, and advanced features.