Convert XLS to XLMX

Understanding xls and xlsx file formats

XLS is the default file format for Microsoft Excel workbooks created in versions prior to Excel 2007. It is a binary file format that stores spreadsheet data, formulas, charts, and macros. XLSX, introduced with Excel 2007, is based on the Office Open XML standard and uses ZIP compression to store data in a more efficient and robust way. XLSX files are more secure, less prone to corruption, and support newer Excel features.

Why convert xls to xlsx?

Converting XLS to XLSX is recommended for improved compatibility with modern software, better data integrity, and access to advanced Excel features. XLSX files are also smaller in size and less susceptible to malware.

How to convert xls to xlsx

The most reliable way to convert an XLS file to XLSX is by using Microsoft Excel. Here’s how:

1. Open your XLS file in Microsoft Excel.
2. Go to File → Save As.
3. In the Save as type dropdown, select Excel Workbook (*.xlsx).
4. Click Save.

Best software and online converters

• Microsoft Excel (Windows, Mac): The most accurate and feature-complete method.
• LibreOffice Calc (Free, Windows/Mac/Linux): Open the XLS file and use File → Save As to choose XLSX format.
• Online converters such as Zamzar, CloudConvert, or Convertio: Upload your XLS file and download the converted XLSX file. These are convenient for quick conversions but may not preserve all advanced features.

Tips for successful conversion

• Always back up your original XLS file before converting.
• Check the converted XLSX file for formatting or formula issues, especially if your spreadsheet uses macros or complex features.
• For batch conversions, consider using Excel’s built-in macro capabilities or command-line tools like unoconv (for LibreOffice users).