Mentigo Icon
MentigoInstrument deck
deck Data & Code Utilities Excel ⇄ JSON Converter
Back to deck
Data & Code Utilities

Excel ⇄ JSON Converter

Convert Excel and XLS spreadsheets to JSON, or turn JSON arrays into downloadable .xlsx workbooks — batch, multi-sheet, and fully in-browser.

Runs privately in your browser — your input is never uploaded or tracked.

Convert Excel to JSON and JSON to Excel Online

Turn spreadsheets into structured data instantly with this free Excel to JSON converter. Drop an .xlsx or legacy .xls workbook — or a .csv export — and get clean JSON where each row becomes an object keyed by the header row. It works the other way too: paste a JSON array and download a ready-to-open .xlsx Excel file. Everything runs locally in your browser, so confidential spreadsheets never leave your machine.

Built for real workbooks, not just toy data. Multi-sheet files are converted into a JSON object keyed by sheet name, dates are preserved as ISO strings, and you can batch several spreadsheets at once — the output is keyed by file name so a whole folder of exports becomes one JSON payload. When generating Excel from JSON, an object of arrays becomes a multi-sheet workbook, making it the fastest way to hand data to analysts, seed a database, or feed an API.

How to Convert Excel to JSON (and Back)

  1. Choose a direction

    Use the toggle to pick Excel → JSON or JSON → Excel depending on what you have.

  2. Drop your file or paste JSON

    Drag an .xlsx, .xls, .csv, or .ods file onto the drop zone — or paste a JSON array of objects to build a workbook.

  3. Review the result

    For Excel → JSON, check the structured JSON output; each sheet and row is mapped automatically with the header row as keys.

  4. Copy or download

    Copy the JSON to your clipboard, download it as a .json file, or download the generated .xlsx workbook.

Why Use This Excel ⇄ JSON Converter?

  • Reads .xlsx and legacy .xls

    Handles modern Excel workbooks and old binary .xls files, plus CSV and OpenDocument (.ods) spreadsheets.

  • Multi-sheet & batch

    Every worksheet becomes its own JSON key, and multiple files are merged into one payload keyed by file name.

  • JSON back to real Excel

    Generate a genuine .xlsx workbook from a JSON array, or a multi-sheet workbook from an object of arrays.

  • Header-aware rows

    The first row is used as object keys by default, or switch it off to get raw row arrays for headerless sheets.

  • 100% private

    Parsing and workbook generation happen entirely in your browser — spreadsheets are never uploaded to a server.

Frequently Asked Questions

How do I convert an Excel file to JSON?

Drop your .xlsx or .xls file onto the Excel → JSON drop zone. Each worksheet is parsed with the first row as headers, and every data row becomes a JSON object. You can then copy or download the result.

Can I convert JSON back into an Excel spreadsheet?

Yes. Switch to JSON → Excel, paste a JSON array of objects, and download a real .xlsx file. To create multiple sheets, pass an object whose values are arrays, e.g. { "People": [...], "Orders": [...] }.

Does it support old .xls files?

Yes. The converter reads both the modern .xlsx format and the legacy binary .xls format, as well as .csv and .ods files.

What happens with multiple sheets or multiple files?

A multi-sheet workbook becomes a JSON object keyed by sheet name. If you drop several files at once, the output is an object keyed by file name so you can batch-convert in one step.

Is my spreadsheet data safe?

Completely. All conversion runs client-side in your browser using JavaScript. Your files are never uploaded, stored, or logged, so financial and private spreadsheets stay on your device.