XLSX (Microsoft Excel Workbook) and CSV (Comma-Separated Values) are built for different jobs. XLSX is typically used for spreadsheets, reports, while CSV is best for data import/export. Converting lets you open, share or upload your files wherever CSV is expected.
How to use the Excel to CSV converter
- Add your XLSX filesClick “Choose Files” or drag and drop them into the box. You can add many files at once — or paste a file with Ctrl+V.
- Choose CSV and adjust settingsCSV is selected automatically. Optionally open Settings to change output options.
- Convert and downloadPress “Convert”. Your CSV files appear instantly — download them one by one or all together as a ZIP.
XLSX vs CSV
XLSX Microsoft Excel Workbook
XLSX is the standard Excel spreadsheet format with multiple sheets, formulas and formatting. Google Sheets, Numbers and LibreOffice open it too.
- Compression
- ZIP-compressed XML
- Features
- Multiple sheets, formulas
- Origin
- 2007, Microsoft
- Best for
- Spreadsheets, reports
CSV Comma-Separated Values
CSV stores a single table as plain text with commas between values. Every database, CRM and spreadsheet can import it.
- Compression
- Plain text
- Features
- Single table
- Origin
- 1972
- Best for
- Data import/export
Why use ConvertMathly?
Files are processed on your device and never uploaded. Close the tab and they are gone.
No account, no daily cap, no queue and no watermark — convert as much as you want.
No waiting for uploads or downloads: results are ready as fast as your device can process them.
Windows, Mac, Linux, Chromebook, iPhone and Android — any modern browser, nothing to install.
Frequently asked questions
How do I convert XLSX to CSV?
Add your XLSX files above, make sure CSV is selected and press Convert. The CSV files are ready to download a few seconds later — no installation or account required.
Is there a file size or daily limit?
No. Since everything runs locally, there are no daily caps, queues or file size limits beyond what your device can handle.
Are my XLSX files uploaded to a server?
No. ConvertMathly converts files entirely inside your web browser using JavaScript and WebAssembly. Your files never leave your computer or phone, which makes it safe for private photos and documents.
Can I convert multiple XLSX files at once?
Yes — add as many files as you like. They are converted one after another and you can download everything in a single ZIP.