XLSX to CSV Convert
Convert an Excel workbook into CSV, one sheet at a time or every sheet at once as a ZIP.
XLSX to CSV is a free online tool that convert an Excel workbook into CSV, one sheet at a time or every sheet at once as a ZIP. It runs entirely in your web browser using JSZip, so files are processed on your own device and never uploaded to a server. There is no sign-up, no file size limit imposed by the site, no watermark and no paid tier.
- Price
- Free: no account, no quota, no watermark
- Category
- Convert
- Where it runs
- In your browser, on your device
- Files uploaded
- None
- Technology
- JSZip
- Settings
- 6
- Works offline
- Yes, after the first visit
About XLSX to CSV
An .xlsx file is a ZIP archive full of XML: one document per worksheet, a shared table of every distinct string, and a style table that says which numbers are really dates. This tool unzips the workbook in memory, reads those parts directly and writes the cell values out as RFC 4180 CSV. Dates stored as Excel serial numbers are turned back into ISO dates when the cell format says they are dates, booleans come out as TRUE and FALSE, and numbers keep the 15 significant digits Excel keeps. Formulas are not recalculated: the value Excel last saved is what you get, which is what every other converter does too.
How to use it
- Drop an .xlsx file on the page, or click to choose one. Macro-enabled .xlsm and template .xltx files work as well.
- Pick a sheet, or leave "All sheets" selected to get one CSV per sheet in a ZIP.
- Set the delimiter, line endings and quoting if the default comma-separated, CRLF output is not what you need.
- Download the CSV, copy it, or open it straight in the CSV Viewer.
The 6 settings
| Setting | What it does | Default |
|---|---|---|
| Sheet | Choose one sheet, or all of them at once as a ZIP. | All sheets |
| Delimiter | Choose from 4: Comma, Semicolon, Tab, Pipe. Tab output is saved as .tsv. | Comma |
| Line endings | Windows (CRLF), which Excel expects, or Unix (LF). | Windows (CRLF) |
| Quote every field | On or off. Off by default: fields are only quoted when they contain the delimiter, a quote or a line break. | Off |
| Add a UTF-8 byte-order mark | On or off. Helps Excel open accented and non-Latin text correctly. | Off |
| Skip empty rows | On or off. Off by default, so row numbers match the original sheet. | Off |
Under the hood
| Runs on | JSZip: unzips the workbook; plain JavaScript reads the sheet XML and writes the CSV |
| Controls | Sheet, Delimiter, Line endings, Quote every field, Add a UTF-8 byte-order mark, Skip empty rows |
Questions
Why did my dates come out as numbers?
Excel stores a date as the number of days since 1900, and only the cell format makes it look like a date. This tool reads that format and converts anything formatted as a date or time into an ISO value like 2026-09-05. If a cell holds a date but was formatted as a plain number, there is nothing to tell it apart from any other number, so it stays numeric.
Does it recalculate formulas?
No. It writes the result Excel saved alongside each formula, exactly as Excel itself does when you Save As CSV. If the file was written by a script that stored formulas without results, those cells will be empty.
Excel shows accented characters as garbage when I open the CSV. Why?
Excel guesses the encoding of a CSV and often guesses wrong for UTF-8. Turn on "Add a UTF-8 byte-order mark": the three invisible bytes at the start tell Excel exactly what it is looking at. Leave it off for anything that will be read by code, since some parsers treat the mark as part of the first header.
Can it read old .xls files?
No. The .xls format that Excel used before 2007 is a binary format, not a ZIP of XML, and this tool only reads .xlsx, .xlsm and .xltx. Open the file in Excel, LibreOffice or Google Sheets and save it as .xlsx first.
What happens to merged cells, colors and charts?
CSV has no way to express any of them, so they are dropped. A merged range keeps its value in the top-left cell and the other cells come out empty, which is also how Excel exports it.
How large a workbook can it handle?
Everything is held in memory, so it depends on your device rather than on any site limit. A sheet with a few hundred thousand rows converts in seconds on a laptop; a phone will run out of memory sooner.
Can I use it full screen, or keep a copy offline?
Yes to both. "Full screen" above the tool fills the whole screen (Esc leaves it). "Save as HTML" writes this one tool to a single self-contained file that opens from your own disk without a connection. For everything at once there is a desktop app for Windows, macOS and Linux with all 312 tools inside it.