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Convert XLS to XLSX for Free

by Hung Nguyen

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XLS is the old format of Microsoft Excel documents. Before 2007, it was the standard for worksheets. Since then, Microsoft has improved their formatting to be more compatible with the XLSX format. If you have a file in the old format and you’re here, chances are, you want to turn it into an XLSX file. The manual method to convert XLS to XLSX requires opening the file in Microsoft Excel and using the “Save As” functionality, where you can choose the format you’d like the file to be in. Conventional file formats that you could save to, include Excel Template (.xltx), .HTML, and, of course, the standard Excel Workbook (.xlsx). However, if you don’t have access to the Office software, or your current machine can’t handle opening large XLS files, you can use Smallpdf’s Excel to PDF converter to convert your documents for free.

How To Convert XLS to XLSX Online for Free

  1. First, convert the XLS to PDF.

  2. Click „Export As“ and choose “Excel.”

  3. Wait for the conversion to finish.

  4. All done! Download your XLSX file.

2023-10-23 - Convert XLS to XLSX for Free

How to convert .xls to .xlsx spreadsheets

As you’ve guessed, Smallpdf first saves the XLS file as a PDF before converting it to an XLSX file. As a matter of fact, any PDF file you drag into this converter will be turned into an Excel workbook. Even if it used to be a JPG, PowerPoint, or Word document.

Whether you decide to use Microsoft Office to convert your digital files manually or our online tool is entirely up to your preference. Smallpdf uses the same conversion method as Microsoft Office itself, so the output file will be of the same high quality.

Should I use XLS or XLSX?


As mentioned, XLS is the older Excel spreadsheet that was used prior to the 2007 version release (XLSX) and is a binary interchange file format. On the other hand, the XLSX format, released alongside Excel 2007, offers much higher compatibility with different operating systems. On top of that, this newer version gives you access to the many popular functions we all associate Excel sheets with today: graphics, calculations, pivot tables, and Visual Basic.

XLSX, as opposed to XLS, is an XML file format—where data is stored in a text file that uses XML to define various parameters. I suppose your needs also depend on whether you can open XML documents, compatibility with your current device, or even requirements made by third parties—if you’re sharing files in a work environment. To put it simply: Most likely, your device today is equipped to handle XLSX files.

Can I Convert XLS to XLSX Free of Charge?


The process we’ve described above involves two of our tools—we’ve just combined them to make things easier for you. Both of them, as well as our 20 other PDF tools, are free to use within limits. Once you’ve run out of the limited usage, a 7-day free trial is available for you to take advantage of. Take a peek at our Pro page for more information on all the perks, including unlimited usage, faster upload speed, and offline and batch processing.

If you still have usage left, you can choose from many other converters on our platform to save your files into different formats—not just Excel. Data sources, formatting, colors, and images will be retained as close to the original version as possible. This also applies to other file types from the Microsoft Office family. Converting with the Smallpdf tools is super easy: It actually always follows the same procedure. You drag & drop your document into the converter, and once it’s done working its magic, you download the file in its new format.

While you’re here, why not check out the wide range of tools on our tools page as well? If you need any help or have suggestions for us, we’re just an email away—always here to make PDF easy for you!

Hung Nguyen
Hung Nguyen
Senior Growth Marketing Manager @Smallpdf