How to convert CSV to XLSX
- Choose or drop your CSV files. You can add several at once.
- Check that “To” is set to XLSX.
- Press “Convert to XLSX” and download the results — or all of them as one ZIP.
CSV vs XLSX
CSV — Comma-separated values. CSV is plain text with one row per line and values separated by commas. Almost every app can import it, but it holds one table only — no formatting, formulas or multiple sheets.
XLSX — Excel workbook. XLSX is the Microsoft Excel format. A workbook can hold several sheets with formatting and formulas, and it opens in Google Sheets, Numbers and LibreOffice.
Convert CSV to XLSX when you need a file for spreadsheets people will open and edit. CSV is better suited to importing data into databases, CRMs and other apps.
FAQ
5Are my files uploaded anywhere?
No. The conversion runs in your browser using your own device’s processor. Your files are never sent to a server, so nobody — including us — can see them. You can even disconnect from the internet after the page loads.
Will I lose quality?
Cell values and sheets are carried over to XLSX. Advanced Excel features such as macros, pivot tables and some formatting may not survive the conversion.
Is there a file size or daily limit?
No limits, and no sign-up. Because nothing is uploaded, we don’t pay for your conversions and have no reason to cap them. Very large files are limited only by your device’s memory.
Can I convert many CSV files at once?
Yes. Add as many files as you like; each is converted to XLSX, and “Download all” saves them together as a ZIP.
Does it work on iPhone and Android?
Yes. It works in any modern browser — Safari, Chrome, Firefox or Edge — on phones, tablets and computers. Older or low-memory phones may be slower with very large files.