Convert CSV to XLSX
The fastest way to convert Comma-Separated Values to Microsoft Excel Open XML Spreadsheet online. Free, secure, and works on any device.
1How to convert CSV to XLSX
Drag & drop your CSV file into the box above.
Click "Convert" to transform it to XLSX instantly.
Save your new file to your device.
2Why use Flux Converter?
Zero Data Usage
Files are converted in your browser. No uploading means no data usage and total privacy.
Lightning Fast
Powered by WebAssembly, conversions happen instantly on your device.
No Limits
Convert as many files as you want, of any size.
Universal
Works on Windows, Mac, Linux, Android, and iOS.
3Why convert CSV to XLSX?
Understanding the strengths and limitations of each format helps you decide when converting from CSV to XLSX makes sense. CSV has been used since the 1970s in early computing. Despite having no formal standard until RFC 4180 in 2005, it remains the most universal tabular data format. XLSX was introduced with Microsoft Office 2007 as the successor to the binary XLS format. It uses ZIP-compressed XML for better interoperability.
CSV
XLSXTarget
4Technical Details
| Feature | CSV | XLSX |
|---|---|---|
| Full Name | Comma-Separated Values | Microsoft Excel Open XML Spreadsheet |
| MIME Type | text/csv | application/vnd.openxmlformats-officedocument.spreadsheetml.sheet |
| Category | Code | Document |
| Use Cases | Data export and import, Database migration, Spreadsheet data sharing, Analytics and reporting | Financial reports and budgets, Data analysis and dashboards, Inventory management, Scientific data recording |
| Description | CSV files use commas to separate values. Each line of the file is a data record. Each record consists of one or more fields, separated by commas. | XLSX is the default file format for Microsoft Excel. It stores spreadsheet data in an XML-based format, supporting formulas, charts, and macros. |
5Frequently Asked Questions
What is the difference between CSV and XLSX?
CSV (Comma-Separated Values) and XLSX (Microsoft Excel Open XML Spreadsheet) serve different purposes. CSV files use commas to separate values. Each line of the file is a data record. Each record consists of one or more fields, separated by commas. On the other hand, XLSX is the default file format for Microsoft Excel. It stores spreadsheet data in an XML-based format, supporting formulas, charts, and macros. Converting between them lets you leverage the strengths of each format depending on your needs.
Does converting CSV to XLSX lose quality?
This depends on the formats involved. For data and document formats, conversion typically preserves all content accurately. Our converter uses the best available algorithms to minimize any quality difference.
Is it safe to convert files here?
ABSOLUTELY. Unlike other sites, we do NOT upload your files to a server. All processing happens locally on your device using advanced browser technologies. Your files never leave your computer.
Is this service really free?
Yes, 100% free. No hidden fees, no watermarks, and no registration required. We support ourselves through non-intrusive advertising.
When should I use CSV instead of XLSX?
CSV is best for: Data export and import and Database migration. XLSX is better for: Financial reports and budgets and Data analysis and dashboards. Choose whichever format best fits your workflow and compatibility requirements.
Can I convert CSV on mobile?
Yes! Our converter works on iPhones, iPads, and Android devices. All processing happens in your browser — no app download needed.
Privacy Guarantee
Your files are yours. We do not store, view, or claim ownership of any content you convert. Processing is done entirely in your browser.