Free web tool

XLSX to CSV

Convert Excel workbooks (.xlsx) to CSV files, the first sheet or every sheet. Dates come out as dates, formulas as their results, and text exactly as typed. The workbook is read on your device. Nothing is uploaded.

Drop Excel workbooks here Choose files XLSX and XLSM, up to 50 MB each.

Options

Sheets First sheet All sheets, as a zip

Separator Keep text that starts with = + - @ from running as a formula in Excel Add a byte-order mark, so Excel on Windows shows accented letters

Bytes of your files sent anywhere: 0

Files are read and converted in this tab, in a background worker. The only requests the page makes are for its own scripts. Your files are never sent anywhere.

How it works

An .xlsx file is a zip of XML files: one lists the sheets, one holds the text that cells share, one the cell styles, and one each sheet's cells. This page opens the zip with JSZip, served from this site, and reads those parts in a background worker in this tab.

Each cell is written as the workbook stores it. Dates are stored as day counts and shown as dates only through their format, so the page reads the format and writes 2026-11-03 rather than 46329. A formula gives the result Excel saved with the file. Empty cells and rows stay empty, so columns line up.

Text that starts with =, +, - or @ was harmless in the workbook but can run as a formula when Excel opens a CSV. With the first option on, such text gets an apostrophe in front, which Excel hides. Numbers are never changed, so -5 stays -5.

How to convert XLSX to CSV

Pick the sheets and separator. First sheet for a one-sheet export, All sheets for a zip with one CSV per sheet. Comma suits most tools; semicolon suits Excel where a comma is the decimal mark.
Add the workbooks. Drop the .xlsx files on the box, or click it to choose them.
Check the row. Each row says how many rows were read and notes hidden sheets or formulas without a saved result.
Download. Download each CSV from its row, or use Download all as .zip.

Limits

Up to 50 MB a workbook, 100 MB of data in a sheet once unpacked, and 5 million cells.
Numbers are written as stored, not as displayed: a cell shown as 12% is written 0.12, and currency signs and thousands separators are left out. An ID typed as a number with more than 15 digits has already been rounded inside the workbook.
The older .xls format and workbooks protected with a password cannot be read. Save them as an unprotected .xlsx first.
Charts, images, comments and cell colors are not part of a CSV.
The CSV is UTF-8. Excel on Windows needs the byte-order mark option to show accented letters correctly; R, Python and most other tools read it either way.

Questions

Are my files uploaded?

No. The page reads each workbook with your browser and converts it in a background worker in this tab. There is no server step. The meter under the drop zone counts the bytes the page and its worker send while they work, so you can check this yourself. The only things the page downloads are its own scripts.

How are dates written?

As ISO 8601: 2026-11-03 for a date, 2026-11-03 14:05:00 for a date and time, 14:05:00 for a time. Excel stores dates as day counts, and the page reads each cell's format to tell a date from a number. Workbooks from old Mac Excel that count from 1904 are read correctly too.

What happens to formulas?

Each formula gives the result Excel saved in the file, as Excel's own Save as CSV does. A workbook made by a program that writes formulas without results has empty cells there; the row says how many. Opening it in Excel and saving it once stores the results.

Why does some text start with an apostrophe?

Text that starts with =, +, - or @ can run as a formula when Excel opens a CSV, which is how malicious spreadsheets spread. The apostrophe makes Excel show it as text. Turn the option off if the CSV is for R, Python or a database, which do not run formulas.

Can I convert every sheet?

Yes. Choose All sheets and each sheet becomes its own CSV, named after the sheet, in one zip. Hidden sheets are included, and the row names them. Chart sheets have no cells and are skipped.

Is it free?

Yes. There is no account, no watermark and no limit beyond the sizes above.

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