Office tool / 10
CSV to XLSX Converter
Turn raw comma-separated data into a native, formatted Excel workbook instantly without uploading sensitive spreadsheets to remote servers.
How to convert CSV to an Excel workbook
Select CSV File
Drag your `.csv` file into the upload zone or choose a file from your device.
Build Workbook
Click "Convert to XLSX". SheetJS converts the delimiter structure into native Excel OpenXML cells.
Download Excel File
Download your new `.xlsx` workbook ready to open in Microsoft Excel, Google Sheets, or Apple Numbers.
Your business numbers, customer email lists, and analytics records are never sent across the internet. The XLSX binary is synthesized directly in your browser's local RAM.
Why convert CSV files into real XLSX workbooks?
Opening raw CSV files directly in Excel often results in common formatting errors. Converting to XLSX resolves these headaches:
Fixes Scrambled UTF-8 Characters
Excel frequently mangles non-ASCII and international characters when opening raw CSVs. An XLSX workbook enforces clean UTF-8 encoding universally.
Prevents Number & Date Truncation
Stops Excel from converting long ID codes or telephone numbers into confusing scientific notation (e.g. 1.23E+11).
Ready for Formulas & Charts
Native XLSX workbooks support conditional formatting, pivot tables, multi-column filters, and formulas without prompting file save warnings.
Professional Client Deliverable
Deliver polished, formatted spreadsheets to clients, managers, and accounting departments rather than raw, unformatted text files.
Frequently Asked Questions
Will this workbook open in Google Sheets and Apple Numbers?
Yes. The output is a standard Office OpenXML `.xlsx` file compatible with Microsoft Excel, Google Sheets, Apple Numbers, LibreOffice, and mobile spreadsheet apps.
Are large CSV files supported?
Yes. Files containing tens of thousands of rows can be processed in seconds because the conversion utilizes your local computer's processor without network bottlenecks.
Can this tool handle semicolons or tab-delimited files?
Yes. SheetJS automatically detects common delimiter patterns including commas, semicolons, and tabs.