Excel to CSV Converter

Convert an Excel (.xlsx) file to CSV format. The file is processed entirely in your browser and is never sent to a server.

Usage Tips

  • The generated CSV includes a UTF-8 byte-order mark (BOM) at the start, so it won't display garbled characters when opened in Windows Excel.
  • If the Excel file contains multiple sheets, you can pick which one to convert from the dropdown menu. Only the selected sheet is converted to CSV.
  • Excel formulas and cell formatting (colors, borders, fonts, etc.) aren't preserved in the CSV output — CSV is a plain-text format that only stores computed values.
  • The file is processed entirely in your browser (client-side) and is never uploaded to a server, so it's safe to use even with sensitive data.

Frequently Asked Questions

If there are multiple sheets, a dropdown menu appears so you can choose which one to convert. Only the content of the selected sheet is converted to CSV; the other sheets aren't included.

The output is UTF-8 with a byte-order mark (BOM). Adding the BOM prevents garbled characters when the file is opened directly in Windows Excel.

No. Since CSV is a plain-text-only format, formulas are converted to their computed result values, and formatting such as colors, borders, and fonts isn't preserved — it's lost in the conversion.

Yes. We provide a separate, dedicated tool for the reverse direction (CSV to Excel). Please use that tool if you need to convert a CSV file into Excel format.
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Side Note — Why CSV Went So Long Without an Official Standard

CSV (Comma-Separated Values) has been in use since the 1970s, but surprisingly, a formal specification wasn't established until 2005, when RFC 4180 became the first official reference. For decades before that, CSV was little more than a loosely shared convention, and details like the delimiter character, quoting rules, and line-ending style varied subtly from one piece of software to another, producing a whole family of incompatible "dialects."

Those dialect differences haven't fully gone away even today. Excel, depending on regional settings, sometimes uses a semicolon instead of a comma as the delimiter (since a comma would clash with its use as the decimal separator in many locales), and the default character encoding differs between the Windows and Mac versions of Excel — so files sharing the same ".csv" name can still behave subtly differently depending on where they came from. This tool generates CSV that complies with RFC 4180, including proper double-quote escaping, so its output is broadly compatible with spreadsheet applications and database tools alike.

On the encoding side, Excel on Japanese Windows tends to save CSV files as Shift-JIS, while Google Sheets and Mac Excel tend to lean toward UTF-8. This tool always outputs UTF-8 with a BOM when converting Excel to CSV, so the result opens correctly in Windows Excel without garbled characters.

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