Convert XLS to XLSX Files Online for Free.
Free online tool to convert xls to xlsx files quickly and securely. No installation required – start converting your files in just a few clicks!
Drag and drop your files here or click to upload.
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Maximum file size is 10MB
How It Works
How to Convert XLS to XLSX
Click inside the file drop area to upload your XLS file or drag & drop it.
Select XLSX as the output format and click the 'Convert' button.
Download the converted XLSX file instantly after conversion.
You can also send a link to the converted file via email. (Optional)
Convert Your XLS files to other formats
RunConvert.com can convert your XLS files to these other formats:
Convert Your XLS files to other formats
Convert Files to XLS Format
RunConvert.com supports these converters to XLS format:
Convert Files to XLS Format
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Frequently Asked Questions
Here are some common questions and answers about xls file conversions ask by our users on RunConvert.com.
Frequently Asked Questions
Q: Can I edit my spreadsheet after converting it to PDF?
A: Not really. PDFs aren’t built for editing like spreadsheets are. You can annotate or highlight, but serious edits? You’ll need to go back to the spreadsheet.
Q: Is it safe to convert spreadsheets online?
A: Yep, as long as you're using a trusted service like RunConvert. We don’t keep your files after conversion, and everything’s encrypted. Your secrets are safe with us!
Q: Can I preview how the PDF will look before converting?
A: We’re building a live preview feature! For now, you’ll need to download and check—conversions are quick, so it’s easy to retry.
Q: How can I make sure the data types stay correct after conversion?
A: Great question! Keep consistent formatting in your original file—especially dates and numbers. And double-check after converting, just in case.
Q: Do formulas still calculate after converting XLSX to ODS?
A: In most cases, yes. Excel and LibreOffice play nicely together—but complex macros or newer functions might act up a bit.
Q: What’s the difference between XLS and XLSX?
A: Good question! XLS is the older Excel format, while XLSX is newer, smaller, and more efficient. It’s kind of like upgrading from a flip phone to a smartphone.
Q: Can I convert XLSX to CSV?
A: Absolutely! XLSX to CSV is one of the most common conversions. Whether you're prepping data for coding or uploading it into a platform, a CSV keeps things clean and simple.
Q: Can I add a watermark to a spreadsheet before converting to PDF?
A: Not on RunConvert (yet!), but you can add it in Excel first—or use a PDF editor after converting.
Q: What’s the most universal spreadsheet format?
A: CSV, hands down. It’s readable by almost every spreadsheet program, script, and database. It’s the Swiss Army knife of spreadsheet formats.
Q: How do I convert a spreadsheet with password protection?
A: You’ll need to remove the password before uploading. RunConvert can’t convert protected files—for your security!
What is XLS (Excel Spreadsheet)?
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.
XLS files are widely used for business, academic, and personal tasks requiring advanced data analysis, visualization, and reporting.
How to open XLS?
XLS files can be opened using spreadsheet programs like Microsoft Excel, LibreOffice Calc, or Google Sheets. These programs display data in a tabular format, preserving the cell structures, formulas, and formatting.
To open XLS files in Excel or Google Sheets, simply double-click the file or import it into the application.
XLS is Developed by: Microsoft
XLS was Released on: 1985
Useful Links for XLS:
How to convert XLS?
You can convert XLS files to other formats, such as CSV, JSON, or PDF, using online file converters or within spreadsheet programs. Simply upload your XLS file and select the desired output format.
In Microsoft Excel or LibreOffice, you can also save your XLS files in various other formats, like CSV or PDF, for compatibility with different applications.
What is XLSX (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).
XLSX files can store multiple sheets, data tables, charts, graphs, and more complex data structures. This format is widely used for organizing, analyzing, and visualizing data.
How to open XLSX?
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.
XLSX is Developed by: Microsoft
XLSX was Released on: 2007
Useful Links for XLSX:
How to convert XLSX?
You can convert XLSX files to other formats, such as CSV, PDF, or JSON, using online file converters. Upload the XLSX file and choose the desired output format.
Many spreadsheet applications like Excel also allow saving XLSX files in other formats, enabling cross-platform compatibility.
What Our Users Say
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Saved me hours of work
I had to convert multiple PDFs to Word for editing. This tool made it so easy and preserved all the formatting perfectly. The batch processing feature is a game changer.
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As a graphic designer, I need reliable conversion tools. This site delivers professional quality every time. The image conversions maintain resolution and color accuracy.
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Fast and reliable
I've tried many conversion tools but this one is by far the fastest and most reliable. No watermarks, no quality loss, and the interface is so intuitive.
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