Convert XLS to XLSX Files Online for Free.

Convert XLS to XLSX online instantly. Free, fast, and secure.

XLS (Excel Spreadsheet) is a proprietary file format developed by Microsoft for storing spreadsheet data, including rows, columns, and data cells. The format supports complex data like formulas, charts, and formatting. It’s typically used in XLS (Excel Spreadsheet)?.

XLSX (Excel Spreadsheet) is a file format used by Microsoft Excel to store spreadsheets. It is a more modern and efficient version of the older XLS format and is based on XML (Extensible Markup Language). Commonly found in XLSX (Excel Spreadsheet)?.

Why Convert XLS to XLSX?

• To make files easier to open across devices.
• To ensure your file size is smaller for faster sharing.
• To avoid needing specific apps to open the file.

Benefits of This Conversion

• Improved compatibility across browsers and apps.
• Better organization by converting to standard formats.
• Optimized performance for web or mobile use.
• More secure sharing and reduced editing risk.

Use Case Scenarios

• You recorded audio as XLS, but need XLSX to save space.
• You’re importing spreadsheet data from XLS into a system that only accepts XLSX.
• Your website needs a lightweight version of your XLS to upload as XLSX.

Conversion Tips

• Use trusted online converters to protect your data.
• Avoid converting lossy formats multiple times.
• Always back up your original file before converting.

Programs That Open XLSX Files

• XLSX files can be opened using spreadsheet programs like Microsoft Excel, Google Sheets, LibreOffice Calc, and Apple Numbers. These applications fully support the features of XLSX files, such as multiple sheets, formulas, and charts.
• To open XLSX files in Excel or Google Sheets, simply double-click the file or import it directly into the application.

Did You Know?

• CSV files are just plain text — super lightweight!
• Did you know? PDF stands for Portable Document Format.
• Converting from DOCX to PDF ensures no fonts get lost.

Useful Resources