What happens to multiple sheets?

Each worksheet becomes its own CSV file.

Why are my dates numbers in other converters?

Excel stores a date as a count of days since 1900 and relies on formatting to display it. This converter reads that formatting, so dates come out as dates.

Is my spreadsheet uploaded?

No. The workbook is unzipped and parsed in your browser — useful for payroll, customer lists or anything you shouldn't hand to a website.

Convert Excel (XLSX) to CSV

Turn every sheet of an .xlsx workbook into CSV in your browser — with real dates, not serial numbers. Nothing uploaded.

Open the converter

Drop an Excel .xlsx file and choose CSV. Every worksheet in the workbook is converted, one CSV per sheet, rather than silently keeping only the first.

Excel stores dates as numbers — 45231 is a day in late 2023 — and a lot of converters hand you those numbers. This reads each cell's number format, including custom formats, and writes the date you actually see in Excel.

Formula cells export the value Excel last calculated and saved, which is what you see on screen. The formula itself isn't recomputed, so a workbook saved by Excel or LibreOffice converts exactly as it looked.

Worth knowing. Only the modern .xlsx format is read; the old binary .xls from Excel 97–2003 is a different format and isn't supported — open it in a spreadsheet app and save it as .xlsx first. OpenDocument .ods files work the same way as .xlsx.

Questions

What happens to multiple sheets?: Each worksheet becomes its own CSV file.
Why are my dates numbers in other converters?: Excel stores a date as a count of days since 1900 and relies on formatting to display it. This converter reads that formatting, so dates come out as dates.
Is my spreadsheet uploaded?: No. The workbook is unzipped and parsed in your browser — useful for payroll, customer lists or anything you shouldn't hand to a website.

Everything the converter reads and writes →

Runs entirely in your browser. The file is never uploaded, so there is nothing for us to store, log or lose. No account, no watermark, no size paywall.