CSV to Excel (XLSX) Converter
Opening a CSV directly in Excel often breaks accents, dates and columns. Convert it to a real .xlsx workbook instead: correct encoding, numbers stored as numbers, a frozen bold header and readable column widths.
Runs in your browser
How to use
- Drop a CSV or TSV file.
- Choose number conversion and header styling.
- Click Convert to Excel and download the .xlsx.
How it works
The CSV is parsed in your browser (RFC 4180, delimiter auto-detected) and written as an Office Open XML workbook with the write-excel-file library. Numeric-looking values become number cells so formulas work; values with leading zeros stay text so postcodes and phone numbers aren't changed.
Column widths are estimated from the first 200 rows.
Examples
- Bank export
- A semicolon-separated statement with accents → an .xlsx that opens correctly in any Excel locale.
Common uses
- Opening exports from banks, shops and CRMs
- Sharing data with Excel users
- Preparing reports
Privacy & security
This tool runs entirely in your browser. Your files and text are never uploaded to our servers — processing happens on your device and results are created locally. How each tool handles files
Frequently asked questions
Why not just open the CSV in Excel?
Excel guesses the encoding and delimiter from your system settings, which often garbles accents and columns.
Are dates converted?
Dates stay as text to avoid ambiguous day/month interpretation.
Last updated: