Convert Excel workbooks to clean CSV, entirely in your browser
=SUM(B1:B2)); and the file downloads as UTF-8 with a BOM so Excel opens accents like Müller correctly. The conversion runs locally with the SheetJS engine — payroll spreadsheets and client lists never touch a server.Click or drag an Excel file here (.xlsx, .xlsm, .xlsb, .xls, .ods)
| Format | What It Is | Converts Here? | Notes |
|---|---|---|---|
.xlsx | Office Open XML workbook (Excel 2007+) | ✅ | The standard modern format |
.xlsm | Macro-enabled workbook | ✅ | Macros are dropped — CSV has no code |
.xlsb | Binary workbook (large-file format) | ✅ | Faster for huge workbooks; sheets convert the same |
.xls | Legacy binary format (97–2003) | ✅ | Max 65,536 rows per sheet |
.ods | OpenDocument spreadsheet | ✅ | LibreOffice / OpenOffice format |
CSV itself is plain text: one table, no formatting, no formulas, no multiple sheets — which is exactly why it's the universal interchange format for imports, scripts, and databases.
| Cell in Excel | CSV Output | Rule Applied |
|---|---|---|
Widget | Widget | Plain text passes through |
4, 9.5 | 4, 9.5 | Numbers export as displayed values |
=SUM(B1:B2) showing 3,500 | 3500 | Formulas export cached computed values |
| Date 2026-03-15, format m/d/yy | 3/15/26 | Dates export in the cell's display format |
name, co (contains comma) | "name, co" | Comma triggers quoting (RFC 4180) |
say "hi" | "say ""hi""" | Quotes double inside quoted cells |
| Cell with a line break | "line↵break" | Embedded newlines are quoted |
Müller | Müller | UTF-8 throughout; BOM for Excel |
An .xlsx file is a ZIP archive of XML files — sheet data, shared strings, styles, and metadata. The converter (SheetJS Community Edition, Apache-2.0, vendored on this page) parses that structure in your browser's memory, reconstructs the cell grid, and serializes each row as comma-separated text following RFC 4180 quoting. Nothing is executed from the workbook; macros never run; nothing is transmitted.
Take a workbook whose first sheet holds a four-row parts table — header Item,Qty,Price, then Widget,4,9.5, Gadget,2,27.25, Doohickey,10,3.1. The sheet's range is A1:C4, so the CSV is exactly four lines: the header plus three data rows, values verbatim, no quoting needed since no cell contains a comma, quote, or newline. Add a =SUM row below and Excel has already cached its computed value, which is what the CSV receives (3,500 in our test — not the formula text). A second sheet in the same workbook appears as its own tab; each exports as its own CSV file.
The SheetJS engine is served from this site (pinned version, Apache-2.0) and every conversion happens through the browser's FileReader and Blob APIs. Open the network tab while converting: zero requests. Spreadsheets with payroll, PII, or unreleased financials stay on your machine, and the page keeps working offline after it loads.
Use a browser-based converter like this one: drop the workbook, pick the sheet, click download. The SheetJS engine parses the file locally in your browser's memory and hands back the CSV — your budget, payroll, or client data never touches a server. Upload-based converters can't make that promise, and many free tiers retain or scan files.
After the file loads, every sheet appears as a tab above the preview — click the one you want and download its CSV. Excel's own Save As CSV exports only the active sheet, which is the classic multi-sheet annoyance; a picker converts each sheet on demand without opening Excel at all.
CSV has no formulas, so cells export their values. Excel files store each formula's last computed result alongside the formula itself, and that cached value is what appears in the CSV — a SUM(B1:B2) cell that shows 3,500 in Excel exports as 3500. Only files saved by unusual tools without cached values fall back to the formula text.
Excel stores dates as serial numbers with a display format; the CSV converter writes what the cell displays — March 15, 2026 in a cell formatted m/d/yy exports as 3/15/26. If you need a strict date format, format the column in Excel first (the CSV inherits it), or expect to re-parse dates on import with your locale's rules in mind.
Yes — per the CSV standard (RFC 4180), any cell containing a comma, a double quote, or a line break gets wrapped in double quotes, and embedded double quotes are doubled: a cell reading say "hi" exports as "say ""hi""". Correct CSV readers undo this on import. Semicolon-separated locales can flip the delimiter; this tool writes commas.
Older Excel assumes the system code page when opening CSV files directly, so accented characters (Müller, Ünal, café) turn to mojibake. The fix is a UTF-8 BOM — three marker bytes at the file start that tell Excel the encoding. This tool adds the BOM by default (toggle it off for systems that choke on it, like some Unix pipelines).