Convert CSV to XLSX Files Online for Free.
Free online tool to convert csv 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 CSV to XLSX
Click inside the file drop area to upload your CSV 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 CSV files to other formats
RunConvert.com can convert your CSV files to these other formats:
Convert Your CSV files to other formats
Convert Files to CSV Format
RunConvert.com supports these converters to CSV format:
Convert Files to CSV Format
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Frequently Asked Questions
Here are some common questions and answers about csv file conversions ask by our users on RunConvert.com.
Frequently Asked Questions
Q: Are my spreadsheet files stored permanently on RunConvert?
A: No way. Files are deleted shortly after conversion—we don’t keep copies, and we don’t snoop. Your data’s your business.
Q: Does RunConvert compress spreadsheet files?
A: We don’t compress them by default, but the resulting files are often smaller—especially if converting from XLS to XLSX or to CSV.
Q: Why is my date format changing during conversion?
A: It’s usually a locale issue—some formats use MM/DD/YYYY, others DD/MM/YYYY. Be sure to set your region correctly before saving or converting.
Q: Are converted files virus-free?
A: Absolutely. We don’t add anything to your files—just convert them. Always scan downloads if you’re extra cautious though!
Q: Why do some numbers change when I open a converted file?
A: Sometimes Excel auto-formats things weirdly—like turning long numbers into scientific notation. Try formatting cells as text before converting.
Q: Why do some formats lose cell formatting?
A: Some file types just don’t support that info. CSV, for example, only stores plain text—no colors, no borders, just the facts.
Q: How do I convert a spreadsheet for print?
A: Convert it to PDF—it locks everything in place. Make sure your print settings (like fit to page) are right before converting.
Q: Can I use RunConvert to convert spreadsheets for school projects?
A: Yes, it’s perfect for students! Fast, free, and no account needed—ideal for submitting homework in the right format.
Q: Can I convert a spreadsheet into JSON or XML?
A: RunConvert doesn’t support that just yet, but it’s on the roadmap. For now, you can use tools like Excel-to-JSON converters online.
Q: Is there a difference between .xls and .xlsx conversion?
A: .XLS is older and bulkier. .XLSX is newer, smaller, and faster. We recommend upgrading during conversion when possible.
What is CSV (Comma-Separated Values)?
CSV (Comma-Separated Values) is a simple text-based file format used for storing tabular data, such as spreadsheets or databases. Each line of a CSV file represents a row, and each value within a row is separated by a comma.
CSV files are commonly used for data exchange between different applications and are easily opened and edited by spreadsheet programs like Microsoft Excel, Google Sheets, and other data processing tools.
How to open CSV?
CSV files can be opened using spreadsheet programs such as Microsoft Excel, Google Sheets, or LibreOffice Calc. You can also open them using text editors like Notepad or Sublime Text, although they won't display the data in a table format.
To open CSV files in Excel or Google Sheets, simply double-click the file or import it into the application.
CSV is Developed by: International Organization for Standardization (ISO)
CSV was Released on: 1983
Useful Links for CSV:
How to convert CSV?
You can convert CSV files to other formats, such as Excel (.xlsx), JSON, or TSV (Tab-Separated Values), using online file converters. Simply upload your CSV file, choose the desired output format, and let the converter do the work.
Many spreadsheet applications like Excel also allow saving CSV files in various formats for easier use across different platforms and 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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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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