Convert XLS to XLSX

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You have the option to convert your xls file to xlsx, as well as a variety of other formats, using our free online converter.

How to convert xls to xlsx?

How to convert xlsx to xls?

Step 1

Upload xls-file

You can select xls file you want to convert from your computer, Google Drive, Dropbox or simply drag and drop it onto the page.

Step 2

Select «to xlsx»

Choose xlsx or any of the other 200+ supported formats you'd like to convert to.

Step 3

Download your xlsx file

Please wait for the conversion to complete, then click on the download button to obtain your converted file in the xlsx format.

Best tool to convert xls to xlsx

xls to xlsx Fast and easy

Simply drag and drop your xls files onto the webpage, and you'll be able to convert them to xlsx or over 250 different file formats, all without having to register, provide an email address, or include a watermark.

Secure xls to xlsx Conversion

As soon as you upload your xls files, we instantly delete them. Converted files are then deleted after 24 hours. Furthermore, we ensure that all file transfers are secure through advanced SSL encryption.

No Software Installation Required

You don't have to go through the hassle of installing any software. We handle all xls to xlsx conversions in the cloud, which means that none of your computer's resources will be used in the process.

Microsoft Excel Binary File Format

Extension	.xls
Category	🔵 documents
Programs	🔵 Microsoft Office 🔵 LibreOffice 🔵 Kingsoft Office 🔵 Google Docs
Main program	🔵 Microsoft Office
Description	🔵 .xls The .xls format is the default file format for spreadsheets created in Microsoft Excel, particularly in versions before Excel 007. This binary file format can store data in cells organized in rows and columns, and it supports formulas, charts, graphs, and various formatting features to manipulate and visualize dataThe .xls format was commonly used in business, finance, and any field requiring data analysis and presentation but has since been largely replaced by the more advanced .xlsx format.
Technical details	🔵 The `.xls` format, primarily for Microsoft Excel versions before 2007, stores spreadsheet elements like worksheets, formulas, and macros. As a proprietary binary format by Microsoft, its undocumented internal structure made third-party software compatibility challenging. This format includes binary records encapsulating data, formatting, and embedded objects, supporting multiple worksheets, various functions, and inter-sheet referencing. `.xls` files may contain Visual Basic for Applications (VBA) macros, enabling automation and complex calculations. It's supported not just in Excel but also in applications like OpenOffice Calc, with options to convert between `.xls` and other formats like `.xlsx`. Despite security concerns with macros, `.xls` is still used, mainly for its compatibility with older Excel versions and legacy systems, although the newer `.xlsx` format, introduced in Office 2007 with XML and ZIP technologies, offers improved efficiency and security.
Developer	🔵 Microsoft
MIME type	🔵 application/vnd.ms-excel

Office Open XML Document

Extension	.xlsx
Category	🔵 documents
Programs	🔵 Microsoft Office 🔵 LibreOffice 🔵 Kingsoft Office 🔵 Google Docs
Main program	🔵 Microsoft Office
Description	🔵 .xlsx (Microsoft Excel Open XML Spreadsheet) The .xlsx format is the default file format for spreadsheets created in Microsoft Excel, starting with Excel 007 and later versions. It's part of the Office Open XML specification and uses XML and ZIP compression for smaller file sizesThe .xlsx format supports complex spreadsheets with data, formulas, charts, pivot tables, and various formatting. It is more efficient and secure compared to the older .xls format and is widely used in business, education, and personal data organization.
Technical details	🔵 Introduced in Excel 2007 as part of the Office Open XML (OOXML) standard, the `.xlsx` format is a notable advancement from the `.xls` format. It employs XML within a ZIP archive structure for improved data readability and efficient organization of elements like worksheets and shared strings. This format supports extensive datasets, allowing up to 1,048,576 rows and 16,384 columns per sheet, and includes advanced features like formulas, charts, pivot tables, and VBA macros. The use of shared XML files optimizes file size. `.xlsx` enhances cross-platform interoperability, includes security features like digital signatures and encryption, and has a macro-enabled `.xlsm` variant. Its XML structure minimizes file corruption risks and aids in data recovery. Widely compatible with modern spreadsheet software and older Excel versions, `.xlsx` has significantly enhanced Excel workbook functionality and efficiency, making it a preferred format for contemporary spreadsheet tasks.
Developer	🔵 Microsoft
MIME type	🔵 application/vnd.openxmlformats-officedocument.spreadsheetml.sheet

FAQs on xls to xlsx Conversion

❓ How do I change xls to xlsx?

To get started, either pick a file you want to convert from xls and select it or drag and drop it into the conversion tool. Next, select the desired format that you wish to convert your file to. Once you have selected the format, click the "convert" button and wait for the tool to finish converting your file.

⏳ What is the estimated time it will take to convert xls to xlsx?

Typically, image conversions only take a few seconds, so you can expect a speedy conversion when changing xls to xlsx.

🛡️ Can I trust OnlineConvertFree to convert xls to xlsx securely?

Absolutely! We take your security seriously, and guarantee the protection of your uploaded and converted files. No one will have access to your information since we delete all files once the conversion process is complete. You can trust that all types of conversions, including xls to xlsx, are 100% safe on OnlineConvertFree.

📱 Is it possible to convert xls to xlsx without having to install any software?

Yes, that's right! OnlineConvertFree doesn't require any installation, which means that you can convert any files, including xls to xlsx, on your computer or mobile device, completely online.