CSV to XLSX Converter
Convert CSV files to the modern Excel .xlsx format — free, private, and instant in your browser.
Convert CSV files to .xlsx, the Office Open XML workbook format that Excel 2007 and later, Google Sheets, LibreOffice, and Apple Numbers all read natively. This page does exactly one job: CSV in, a standards-compliant .xlsx workbook out.
Because the output is a real workbook rather than a renamed text file, you can combine several CSVs into one download — each file becomes its own named sheet — and columns are auto-fit so the result opens readable instead of truncated.
If you are not sure whether you need .xlsx or the legacy .xls format, or you want to choose between them at download time, use the CSV to Excel Converter linked below, which outputs either.
Drop your file here or browse from your device
Accepts CSV, TSV, TXT. Up to 20 files; combined maximum: 10 MiB. Files above this hard limit are rejected before local processing.
Tip: select multiple CSV files to combine them into one workbook, one sheet per file.
How to Convert
- Upload one or more CSV files, or paste your CSV data
- Preview the data and adjust formatting options
- Click Convert to generate the .xlsx workbook
- Download your Excel file
Features
- Outputs standard .xlsx readable by Excel 2007+, Google Sheets, and LibreOffice
- Combine multiple CSV files into one workbook, one sheet per file
- Auto-fit column widths for readable output
- Auto-detects the delimiter (comma, semicolon, tab)
- Runs entirely in your browser — files never leave your device
Use Cases
- Create a modern .xlsx workbook from a CSV export
- Open CSV data in Excel with proper columns and headers
- Merge several CSV files into one multi-sheet .xlsx workbook
Frequently Asked Questions
What is the difference between XLSX and XLS?
.xlsx is the modern Excel format introduced in Excel 2007 and is the right choice for almost everyone. .xls is the older Excel 97-2003 format — use our CSV to XLS converter only if you need that legacy format.
Will the .xlsx file open in Excel and Google Sheets?
Yes. The output is a standard Excel workbook that opens cleanly in Microsoft Excel, Google Sheets, LibreOffice Calc, and Apple Numbers.
Can I combine multiple CSVs into one workbook?
Yes. Select several CSV files and each becomes its own sheet in a single .xlsx workbook.
Is my data uploaded anywhere?
Never. The conversion runs locally in your browser, so your data stays private and works offline.
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