Convert Excel (XLSX) to CSV Online Free

Need your Excel data as plain CSV? AllConvert converts XLSX to CSV instantly, right in your browser. No upload, no account, no Microsoft Office required.

Why convert XLSX to CSV?

CSV is the universal language of data: import tools, databases, CRMs, scripts in Python or R, and almost every web service that accepts a data upload expects CSV, not Excel workbooks. Converting XLSX to CSV strips away formatting, formulas and macros, leaving just the clean rows and columns of values that data tools want.

What happens during the conversion?

AllConvert parses the workbook in your browser and writes the first sheet out as standard comma-separated values, quoting fields where needed. Formulas are exported as their calculated values. If your workbook has multiple sheets, move the one you need to the first position before converting.

Sensitive spreadsheets stay private

Spreadsheets often contain customer lists, financials or HR data. Because AllConvert runs entirely in your browser, the file is never uploaded to any server — there is nothing to trust, because nothing leaves your machine. Need JSON instead? Try XLSX to JSON.

How to convert

1. Drop your XLSX file into the converter box at the top of this page, or click the box to browse.
2. The first sheet is converted to CSV immediately on your device — the file is never uploaded.
3. Click the download button that appears to save the CSV.

The spreadsheet never leaves your device during conversion — no upload, no size limit beyond your own memory — on desktop or mobile.

What doesn't survive the conversion

An XLSX file is a zip archive of XML parts — each sheet, its formatting, and any merged cells or formulas live in separate files inside that archive. CSV has none of that: just rows of text separated by commas, one sheet, no styling. A cell showing =SUM(A1:A10) comes across as whatever number it last calculated to, not the formula itself. Merged cells split back into individual cells, with the value showing only in the first one. Multi-sheet workbooks need exporting one sheet at a time, since CSV has no concept of multiple sheets — only the first one in the file makes it across.

Frequently asked questions

Which sheet of my Excel file is converted to CSV?
The first sheet in the workbook. For a different sheet, move it to the first position in your spreadsheet app before converting.

What happens to formulas during XLSX to CSV conversion?
They're exported as their last calculated value, which is what CSV consumers expect — the formula text itself isn't kept.

Is it safe to convert confidential spreadsheets online?
With AllConvert, yes. The conversion runs entirely in your browser and the file is never uploaded, so confidential data stays on your device.