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XLSX to CSV converter

Convert XLSX to CSV free in your browser. Paste your XLSX on the left, press Convert, and copy clean CSV on the right. No sign-up, no uploads.

Converter

Paste XLSX below, press Convert, and copy the CSV output.

Picking a file reads its first sheet into the input box.

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How the spreadsheet becomes CSV

When you pick a file, the SheetJS library reads the first worksheet into a grid in memory, and the first row becomes the column headers for every row below it. That grid is exactly what you see staged in the input box as JSON, and pressing Convert reshapes it into CSV with types preserved from the cells.

Getting the best results

Press Load sample first to see the exact XLSX shape the converter expects, then replace it with your own data. If a conversion errors, the message names the exact line or token at fault, so fixing the input is usually a one-minute job. For repeated jobs, bookmark the page; your data never leaves the browser.

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XLSX to CSV FAQs

Which part of my spreadsheet gets converted?
Upload any .xlsx or .xls file and the tool reads the first worksheet only, using its first row as the column headers. Blank rows are skipped. If your data lives on another sheet, move or copy it to the first sheet before uploading, or paste the cells as a JSON array of arrays.
Does the CSV handle commas and quotes correctly?
Yes. Any cell containing a comma, quote or line break is wrapped in double quotes with inner quotes doubled, per RFC 4180. The first line is the header row, and the file opens cleanly in Excel, Google Sheets and pandas.
Do cell types survive the conversion?
Numbers, booleans and text come through with their types, and empty cells become empty strings. Dates arrive as Excel serial values, so format date columns as text in Excel first if you need readable dates in the CSV output.
Is there a size limit for XLSX input?
No hard limit, but everything runs in your browser tab, so tens of thousands of rows convert in seconds while millions of rows may slow the page. For very large XLSX files, split them into smaller chunks and convert each separately.
Is my XLSX data private, and who uses this?
Yes. The conversion runs 100% in your browser with the SheetJS library loaded from CDN; nothing is uploaded to any server. Developers, analysts and DBAs use it to move XLSX data into CSV for migrations, reports and config work without installing anything.
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