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Excel (xlsx) to CSV/JSON Converter

A tool that reads Excel (.xlsx / .xlsm / .xls) and ODS files in your browser and converts each sheet to CSV or JSON for download. You can choose how merged cells, dates, and formulas are handled, plus the delimiter and encoding (UTF-8 with BOM or Shift_JIS). Your file is never sent to a server.

Files are not uploaded to a server. They are read and converted inside your browser (in a Web Worker).

Drag and drop an Excel or ODS file

Supports .xlsx / .xlsm / .xls / .ods

How to use

  1. Drag and drop an Excel or ODS file, or load one with "Choose file".
  2. Once loaded, the list of sheets appears. Pick a sheet to see a preview of its first 100 rows and the converted output.
  3. Use "Conversion settings" to choose the output format (CSV or JSON), start row, whether to remove empty rows and columns, and how merged cells and dates are handled. For CSV you can also choose the delimiter, line endings, and encoding.
  4. Save with "Download this sheet", or save every sheet at once with "Download all sheets as ZIP". You can also continue editing the result with "Open in CSV Editor".

About this tool

The Excel (xlsx) to CSV/JSON Converter turns spreadsheet files into CSV or JSON. It's handy when you need data out of a spreadsheet without Excel installed, want a CSV to import into another system, or need JSON that's easy to work with in code.

Date cells can be output as ISO 8601 (2026-01-31), as displayed in Excel, or as serial numbers, and workbooks using the 1904 date system are supported. Merged cells can either keep the value only in the top-left cell or repeat it across the whole range. Formula cells output their calculated values, or the formulas themselves if you prefer.

CSV can be saved as UTF-8 with a BOM so it opens cleanly in Excel, or as Shift_JIS (CP932) for legacy systems. Files are parsed with SheetJS Community Edition (Apache-2.0) inside a Web Worker in your browser, so the page stays responsive with large files and no data is ever sent anywhere.

Frequently asked questions

Can I convert password-protected files?

No. Open the file in Excel, remove the password, save it, and then load it here.

My CSV shows garbled text when opened in Excel.

Save with the "UTF-8 with BOM" encoding. If a legacy system needs Shift_JIS, choose "Shift_JIS (CP932)" instead. Characters that Shift_JIS can't represent (some emoji and symbols) are replaced with "?".

What happens to formulas and macros?

Formula cells output the calculated values saved in the file. Turn on "Output formulas for formula cells" to output formulas such as =SUM(A1:A3) instead. Macros in .xlsm files are never run; only cell values are read.

Is my file sent to a server?

No. Everything from loading to converting and downloading happens in your browser.