OpenNestCSV to XLSX Converter
Convert CSV to Excel Workbook directly in your browser. Your files never leave your device — no uploads, no account, no tracking.
Choose files
or drag & drop here
100% local — your file never leaves this device.
How to convert CSV to XLSX
Choose your CSV file
Select a CSV from your device — click or drag & drop.
Pick XLSX as the output
We auto-detect your file and show XLSX as a recommended target.
Convert & download
Everything runs locally in your browser, then you download the result instantly.
Why use OpenNest to convert CSV to XLSX?
100% local
Your CSV file is converted entirely in your browser — nothing is uploaded.
Free & no account
No signup, no limits. Convert as many files as you need, on any device.
Private by design
No servers, no tracking, no logs. Close the tab and every trace is gone.
Supported input & output
| Input — CSV | .csv · text/csv |
|---|---|
| Output — Excel Workbook | .xlsx, .xls · application/vnd.openxmlformats-officedocument.spreadsheetml.sheet |
FAQ — CSV to XLSX
Is CSV to XLSX conversion free?
Yes — completely free, no account, no signup, and no file limits.
Do I need to upload my CSV file?
No. The conversion runs entirely in your browser; your file never leaves your device.
How do I convert CSV to XLSX?
Select your CSV file, choose XLSX as the target, and click Convert. The result downloads instantly.
Is the output quality preserved?
Conversion is done locally with high-quality output, preserved to the extent the target format allows.