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Convert XLS to XLSX for Free

by Hung Nguyen

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The manual method to convert XLS to XLSX requires opening the file from Microsoft Excel and saving it as another format. Conventional file formats that you could save to, include Excel Template (.xltx), .htm, 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. Download the first file.

  3. Now go to our PDF to Excel tool.

  4. Drag the downloaded file into the green toolbox.

  5. It will now convert to XLSX. Download this file.


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 file saved using Excel that’s then put into our PDF to Excel tool will be converted to an XLSX file—the standard output type for our converter. Whether you decide to use your spreadsheet application 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?


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, and many of the widely used functions that we use every day to date: graphics, calculations, pivot tables, and Visual Basic.

XSLX, as opposed to XSL (a binary file format), 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.

Can I Convert XLS to XLSX Free of Charge?


The two tools we’ve mentioned, that you can use in combination to get a file from XLS to XLSX are both free for occasional use. Better yet, you have access to over 20 free PDF tools on our site. 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 versions of Excel, as possible. This also applies to other file types within the Microsoft Office family. The conversion tools for all of them follow the same steps: drag and drop your document, convert it, then download it.

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.

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

Hung Nguyen
Hung Nguyen
Senior Growth Marketing Manager @Smallpdf