Excel to JSON

Drop an .xlsx, pick a sheet, get JSON or CSV. Nothing is uploaded.

How to convert Excel to JSON

  1. Open the workbook

    Drop an .xlsx or .xlsm file on the page or click to choose one. The workbook is unpacked in a background worker, with progress shown as each part is read.

  2. Choose a sheet and shape

    If the file has several sheets, pick one from the Sheet menu. Choose JSON objects (one object per row, keyed by the header), JSON arrays (one array per row) or CSV, and say whether the first row is a header.

  3. Copy or download

    Check the preview of the first 20 rows, then press Copy, use Ctrl+C with nothing selected, or Download to save the result with the workbook's name and a .json or .csv extension.

Good to know

  • Dates are recognised from the cell's number format and written as ISO text, 2026-09-26 or 2026-09-26 14:30:00. Plain numbers stay numbers and TRUE/FALSE become booleans.
  • Formula cells give their last calculated value, as saved by Excel. The formula itself is not exported.
  • Empty cells become null in JSON and empty strings in CSV. Skip empty rows drops rows with no values at all, and trailing blank rows are always dropped.
  • Without a header row, or where a header cell is blank, columns are named by their letter: A, B, C.
  • Only .xlsx and .xlsm are supported. For an old .xls file, open it in Excel or LibreOffice and save as .xlsx first.
  • The workbook stays loaded in the worker, so switching sheets or options is quick. Large sheets show the first 1 MB of output; Download has everything, and Copy is disabled above 20 MB. Nothing is uploaded.

Questions people ask

Why do my dates show as numbers?

Excel stores dates as day counts and marks them with a number format. Cells formatted as dates are converted to ISO text here. If a column shows plain numbers such as 45000, those cells were not formatted as dates in Excel; apply a date format, save, and convert again.

Can I convert a specific sheet?

Yes. When a workbook has more than one sheet, a Sheet menu appears above the output. The first sheet is selected by default.

What happens to merged cells and formatting?

Only cell values are read. A merged range gives its value in the top-left cell and null in the rest. Colours, fonts, column widths and comments are not exported.

Does it work with .xls or CSV files?

No. The tool reads the .xlsx and .xlsm formats only. For .xls, resave the file as .xlsx in Excel or LibreOffice. CSV can go straight into the CSV to JSON tool.

Is my spreadsheet uploaded?

No. The file is unzipped and parsed in a web worker inside your browser. Nothing leaves your device.