How it works
- Click Open your XLSX to launch the editor in your browser.
- Pick the .xlsx file from your device, or drag and drop it onto the page.
- Choose Download as / Save as and pick CSV.
- The CSV is generated on your device and downloaded — nothing is uploaded.
Most "XLSX to CSV" converters upload your spreadsheet to their servers first. This one does not: it opens the file with the OnlyOffice engine locally, so your data stays private. No Excel, no account, works offline. Try the features you need while online, then use what your browser has saved offline. Opening files from links still needs a connection.
The conversion itself is handled by OnlyOffice's x2t engine compiled to WebAssembly. It targets the common office and text formats — Word, Excel and PowerPoint plus PDF, TXT, HTML and CSV — which makes it a good fit for turning a spreadsheet into a portable CSV. Because it all runs in the browser tab there is no upload queue, no server-imposed size cap, and your data never touches the network. Note that CSV is a flat, single-table format: the active sheet is exported, and each formula is written out as its calculated value.
CSV is the lowest-common-denominator format for data: almost every database, analytics tool and programming language can import it. Exporting a spreadsheet to CSV here is useful when you need to feed a report into another system, share tabular data without shipping a whole workbook, or strip a file down to raw values. And because the export runs on your device, even sensitive data — customer lists, finance exports — stays private.
Frequently asked questions
How do I convert XLSX to CSV here?
Open the XLSX in the editor, then use Download as / Save as CSV — the conversion runs in your browser.
Is my file uploaded to convert it?
No. When you open local files directly on this site, viewing, editing and conversion happen on your device without uploading your documents.
Do I need Excel or an account?
No Excel, no 365 subscription and no sign up.
Can I convert CSV back to XLSX?
Yes — see CSV to XLSX.
Which sheet gets exported to CSV?
CSV holds a single table, so the active sheet is exported. Open the sheet you want first, then save as CSV.
Are formulas exported or their values?
CSV stores plain values, so formulas are written out as their calculated results.
Does the converter work offline?
Yes, with some preparation. Open the files you need online and try editing and exporting, then disconnect to check they work. Clearing browser data may require reconnecting. Files opened from links need a connection.