XLS to XLSX Converter
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How to convert XLS to XLSX online
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What is a XLS file?
XLS is the proprietary spreadsheet format used by Microsoft Excel prior to the introduction of XLSX in 2007. It uses a binary file structure and supports formulas, charts, macros, and formatting.
XLS files remain widely compatible and are still used in many organizations. However, XLSX offers better performance and security.
How to open XLS files
XLS files can be opened using Microsoft Excel, Google Sheets, LibreOffice Calc, and other spreadsheet applications. They support charts, formulas, and formatting.
To ensure compatibility and security, convert XLS to XLSX or ODS using AnyConv or within Excel itself.
Key facts about XLS
- Full name: Microsoft Excel Binary File Format
- Extension: .xls
- MIME type: application/vnd.ms-excel
- Developed by: Microsoft
- Initial release: 1987
Useful links and resources
What is a XLSX file?
XLSX is the default spreadsheet format used by Microsoft Excel since Office 2007. It is based on the Open XML standard and stores data in cells organized by rows and columns.
XLSX files support formulas, charts, formatting, and large data sets. They are widely used for financial modeling, data analysis, and record keeping across industries.
How to open XLSX files
XLSX files can be opened with Microsoft Excel, Google Sheets, LibreOffice Calc, and many other spreadsheet applications. They are the standard format for spreadsheets today.
You can convert XLSX to PDF, CSV, or XLS using AnyConv or via built-in export options in Excel and other tools.
Key facts about XLSX
- Full name: Microsoft Excel Open XML Spreadsheet
- Extension: .xlsx
- MIME type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
- Developed by: Microsoft
- Initial release: 2007
Useful links and resources
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❓ Frequently Asked Questions
- Do I need to register to convert XLS files?Not at all! You can convert XLS to XLSX without signing up or installing anything.
- Is it safe to convert XLS to XLSX on AnyConv?Absolutely. All XLS and XLSX files are securely handled and automatically deleted after 1 hour. Nobody can access your data.
- Will the quality change after converting XLS to XLSX?We do our best to preserve the original quality during XLS to XLSX conversion. The result is accurate and clean.
- How long does it take to convert XLS to XLSX?Most conversions from XLS to XLSX take just a few seconds — even for larger files.
- Can I upload more than one XLS file?Yes, batch conversion is supported. You can convert multiple XLS files to XLSX at once — fast and easy.
- What browsers support XLS to XLSX conversion?All modern browsers! Chrome, Firefox, Safari, Edge — AnyConv runs online and supports converting XLS to XLSX on any platform.