Excel to JSON Converter

What the Excel to JSON Converter Does

This tool takes a spreadsheet and produces JSON that mirrors its rows. The first row is treated as the header, and every row beneath it becomes an object whose property names are those headers, ready to paste into code or an API.

It is the quick way to get tabular data out of Excel and into a format your application can consume, without writing an import script or installing anything.

How It Works

When you drop a file, the tool loads a spreadsheet library in your browser, reads the workbook from the file's bytes, and takes the first worksheet. It maps the header row to keys and each data row to an object, then outputs the whole thing as nicely indented JSON.

Everything happens locally. The spreadsheet is parsed in the page using the file you provide, so the data never leaves your device — there is no upload step and no server involved.

Data source & conversion logic

1. Read the workbook. Parse the dropped .xlsx or .xls file in your browser with a spreadsheet library.
2. Take the first sheet. Select the first worksheet from the workbook to convert.
3. Map headers to keys. Use the first row as the property names for each row object.
4. Output JSON. Turn every data row into an object and return the array as indented JSON.

Row to object mapping

The header row becomes the keys. Only the first sheet is converted, and cells are read as their computed values — a formula returns its result, not the formula text.

Privacy

Your spreadsheet never leaves your device. It is read and converted in your browser with no network request, so nothing is uploaded.

Because the work is local, you can convert spreadsheets containing private or business data without it being stored or sent anywhere.

Nothing persists between sessions — close the tab and the file and its JSON are gone.

Standards & references

• Office Open XML (.xlsx) — The modern Excel file format, an open standard (ECMA-376). The tool reads it, and the older .xls binary format, with a spreadsheet library in the browser.
• Header row as keys — The first row supplies the property names for each row object. If two headers are the same, the library disambiguates them, and a sheet without a header row produces awkward keys.
• First worksheet only — A workbook can hold many sheets, but this tool converts the first one. For other sheets, a sheet splitter or selecting the sheet in Excel first is needed.

Accuracy & Limitations

For a clean sheet with a header row and simple values, the JSON is an exact, faithful representation of the data — each row an object keyed by the headers, ready to use.

It converts the first worksheet only. A multi-sheet workbook yields just the first sheet's data, so move or copy the sheet you want to the front, or split the workbook first, if it is not sheet one.

Cells are read as computed values. A formula comes through as its result rather than the formula text, and numeric or date formatting is read as the underlying value, so a formatted date may appear as a serial number unless it was stored as text.

Empty cells may be omitted from a row's object rather than included as empty, and merged cells or complex layouts do not map neatly to flat rows. It works best on a plain, tabular sheet.

Real-World Use Cases

When to use it — and when not to

For another sheet, split the workbook or move the sheet to the front first. To keep formula text or exact formatting, handle it in Excel before converting. For the reverse direction, use a JSON-to-Excel converter.

Frequently Asked Questions

References

• SheetJS — sheet_to_json (docs)
• Office Open XML (Wikipedia)
• JSON (ECMA-404 / RFC 8259)

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