CSV to XLSX Converter
Convert CSV to Excel (.xlsx) online — free, no signup, browser-based whenever possible. Drop your CSV file and download a proper Excel workbook instantly.
Drop files here, browse
Drop your CSV file here
Max file size: 100 MB
Auto-detect Format
Drop a CSV and it converts to XLSX. Drop an XLSX and it converts to CSV. The mode is set automatically.
Private by Design
SheetJS runs in your browser. Your spreadsheet data is processed locally whenever possible and is not sent to any server.
Preserves Structure
Column headers and data are preserved as faithfully as possible in the output format.
How to convert CSV to XLSX online
- Drop your CSV file onto the drop zone above, or click to browse.
- The tool auto-detects the CSV format and sets the mode to CSV → XLSX automatically.
- Click Convert to XLSX to process your file.
- Preview the first rows to verify the data, then click the download button to save your Excel file.
Why convert CSV to XLSX?
CSV files are widely used to export data from databases, CRMs, and analytics tools, but CSV is plain text with no styling, column types, or sheet structure. Converting CSV to Excel gives you a proper .xlsx workbook you can open in Microsoft Excel, Google Sheets, LibreOffice, or Apple Numbers — and once it is open you can add formulas, filtering, formatting, charts, and PivotTables yourself. A free CSV to Excel converter online saves you the manual import steps entirely.
Convert CSV into an Excel-compatible XLSX file
Each CSV row maps to a spreadsheet row and each column to a spreadsheet column, with the first row kept as the header row at the top. The output is a single worksheet (named “Sheet1”) saved as a standard .xlsx workbook, so it opens cleanly in Microsoft Excel, Google Sheets, LibreOffice Calc, and Apple Numbers. Need to go the other way? Use XLSX to CSV.
Common use cases
- Turning database query exports into a shareable Excel workbook.
- Opening CRM or ERP CSV exports in a familiar spreadsheet.
- Preparing financial reports and reconciliations for review.
- Handing analytics or tracking data to teammates who prefer Excel.
- Packaging client reports as a clean .xlsx file.
Prefer structured data for code instead of a spreadsheet? Convert the same file with CSV to JSON.
CSV parsing and limitations
The converter is built for standard comma-separated CSV. Values that look numeric may be stored as numbers in the workbook, which can drop leading zeros (for example a ZIP code like 02115) — keep those columns as text in your source if exact formatting matters. Only the data itself is written: the converter does not add formulas, styling, or extra worksheets. Conversion happens in your browser, so very large files are ultimately limited by your device's available memory rather than a fixed row cap.
Privacy — your spreadsheet data stays local
This tool uses SheetJS (xlsx) — an open-source JavaScript library that runs directly in your browser. Your spreadsheet file is processed locally on your device whenever possible and is not sent to any server. This makes it suitable for business data, financial exports, and contact lists. That said, always follow your organisation's data policies before using any online tool with confidential or regulated data.
Frequently Asked Questions
Is this CSV to Excel converter free?
Yes — completely free. No account, no signup, and no limits on conversions. This is a free CSV to XLSX converter with no hidden costs.
Is my CSV file uploaded to a server?
No. Conversion runs in your browser using SheetJS. Your data is processed locally whenever possible and is not transmitted to any server.
Will the CSV columns map correctly into Excel?
Yes — the converter reads your CSV and writes each column into its own Excel column. The first row is treated as a header row. Numbers and dates are preserved as faithfully as the data allows.
Can I convert a large CSV file?
Yes — file size is limited only by your browser's available memory. Most CSV files up to a few hundred MB work without issue. Very large files may process more slowly depending on your device.
What is the difference between CSV and XLSX?
CSV is a plain-text file where values are separated by commas — simple and universal, but with no formatting, cell types, formulas, or multiple sheets. XLSX is the modern Excel workbook format, which supports all of those. This tool reads your CSV data and writes it into a clean XLSX workbook you can build on in Excel.
Does the converter add formulas or formatting?
No. It produces a clean, data-only workbook that mirrors your CSV. You can add formulas, filters, formatting, charts, and PivotTables yourself once the file is open in Excel, Google Sheets, or LibreOffice.
Can I open the file in Google Sheets, and do I need Excel installed?
You do not need Microsoft Excel installed to convert. The resulting .xlsx opens in Google Sheets, LibreOffice Calc, and Apple Numbers as well as Excel.
Does it support semicolon-separated CSV?
The converter is designed for standard comma-separated CSV. If your file uses semicolons or another delimiter, convert it to commas first for the most reliable result.
Does it create one worksheet or multiple?
A CSV file represents a single table, so the converter creates a single worksheet (named “Sheet1”) in the output workbook.
Can it preserve leading zeros?
Values that look like numbers may be stored as numbers, which can drop leading zeros (for example 00123 becoming 123). This is standard spreadsheet behaviour; keep such columns formatted as text in your source data if the exact digits matter.