Excel to CSV
Turn an .xlsx workbook into CSV — every sheet, or just the ones you need.
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or drag it here
XLSX or XLSM · one workbook
Your file never leaves your browser during processing
How it works
To convert an Excel file to CSV, drop the .xlsx workbook onto this page, tick the sheets you want, and each one is written as its own CSV file in your browser — the workbook is never uploaded.
An .xlsx file is a zip archive containing the workbook as XML. This page opens that archive in your browser, reads the sheet list, the shared string table, and the cell values, and rebuilds each sheet as a grid of rows. Nothing is sent anywhere, so there is no upload wait and no copy of your spreadsheet on someone else’s server — which matters, because spreadsheets tend to hold exactly the data you would not want sitting in a queue somewhere.
CSV has no concept of a workbook, so a file with several sheets cannot become one CSV without losing information. Rather than silently exporting only the first sheet, which is what most converters do, this one lists every sheet with its row and column count and writes a separate file for each one you tick. Sheets Excel has marked hidden are shown too, but start unticked — they are usually lookup tables rather than the data you came for.
Two conversions need a decision, and both are made explicitly rather than guessed at. Dates are written in ISO form, because a date in a spreadsheet carries no locale: 03/04/2024 means the fourth of March in one country and the third of April in another, while 2024-03-04 means one thing everywhere. Formulas are written as their last calculated value, which is what the file stores alongside them — a browser cannot recalculate a spreadsheet.
The format read here is the modern OOXML one: .xlsx and .xlsm. A legacy .xls file is an entirely different binary format and is rejected with an explanation rather than a parse error; re-save it as .xlsx in Excel, LibreOffice, or Google Sheets first.
FAQ
How do I convert an Excel file with multiple sheets to CSV?
Tick the sheets you want and each becomes its own CSV file, named after the sheet. CSV cannot hold more than one table, so combining them into a single file would lose the boundaries between them.
Why do my dates look different from Excel?
They are written as ISO dates (2024-03-04). A spreadsheet displays a date using the reader’s locale, so exporting it in that display form makes the file ambiguous. ISO is unambiguous and is what databases and scripting languages expect.
Can it open .xls or .xlsb files?
No. Those are binary formats unrelated to .xlsx, which is a zip of XML. The tool detects them and tells you rather than failing oddly — open the file in a spreadsheet application and save it as .xlsx.
What happens to formulas, charts, and cell colours?
Formulas are exported as their last calculated value. Charts, colours, fonts, merged-cell formatting, and images are dropped, because CSV is plain text and has nowhere to put them.
Why do accented characters look wrong when I open the CSV in Excel?
Excel on Windows reads UTF-8 as the system codepage unless the file starts with a byte-order mark. Tick “Add BOM for Excel” and it will read correctly. Leave it off for pandas, databases, and most other tools, which treat the mark as data.
Is my spreadsheet uploaded anywhere?
No. The workbook is unzipped and parsed entirely in your browser, and the monitor under the tool shows zero bytes sent during processing.