How to convert CSV to XLSX
- 1. Add your CSV file
Drag a CSV file onto the box above, or click to browse. - 2. Choose XLSX
XLSX is already selected as the output — just confirm. - 3. Convert & download
Hit Convert and your new file is ready to save in a second.
CSV and XLSX explained
CSV (Comma-Separated Values): A plain-text format for spreadsheet and tabular data that opens anywhere.
XLSX (Excel Spreadsheet): The modern Microsoft Excel spreadsheet format.
Frequently asked questions
Is it free to convert CSV to XLSX?
Yes. Converting CSV to XLSX on SwiftConvert is completely free, with no sign-up, no watermark and no limits.
Are my files uploaded to a server?
No. The conversion runs entirely in your browser, so your files never leave your device — nothing is uploaded, which keeps your data private.
Will I lose quality converting CSV to XLSX?
The conversion keeps as much quality as the XLSX format allows.
Does it work on Windows, Mac, iPhone and Android?
Yes. It runs in any modern browser on any device — there is nothing to install to convert CSV to XLSX.