Excel (XLSX) → JSON

Client

Turn a workbook you already have on disk into JSON for scripts, APIs, or fixtures. Parsing stays in your browser; for pasted CSV use CSV ↔ JSON.

Limits and privacy

Files are read with FileReader in your tab—nothing is uploaded. Very large workbooks can be slow or fail depending on available memory; the UI rejects files above 15 MB. Use a trimmed export or split sheets if you hit that cap.

Learn more: Excel workbooks and JSON

Read a binary .xlsx or legacy .xls file and emit JSON: either one sheet as an array of row objects (header row → keys) or an object mapping every sheet name to its rows.

Why not only CSV?

Many teams still exchange Excel files with multiple tabs, merged cells, or typed columns. Converting in the browser avoids a server upload while still giving you JSON you can pipe into scripts or APIs.

Formulas and formatting

The conversion reads stored cell values, not a full recalculation engine. If totals look stale, open the file in a spreadsheet app, recalculate, save, and try again.

Size and where parsing runs

Workbooks are parsed entirely in your browser. Large files consume RAM like any other client-side parser; the page enforces a modest maximum file size so tabs stay stable on typical hardware. Nothing is sent to Toolcore servers.

Workbook → JSON

?

Parses .xlsx / .xls locally. Formulas appear as cached values when the workbook stores them; empty cells become null.

Export

Common use cases

  • Export a single sheet as an array of objects when the first row holds column names.
  • Dump every sheet into one JSON object for quick inspection before ETL.
  • Grab a one-off export from Finance or Ops for a script without installing spreadsheet drivers.
  • Preview row shape from a template workbook before wiring it into an API or test harness.

Common mistakes to avoid

  • Merged header cells

    Merged regions can produce odd column keys—normalize the sheet in Excel or LibreOffice first if headers look wrong.

  • Expecting formula live evaluation

    You see stored/cached values from the file, not a full recalc engine—open and save in a spreadsheet app if numbers look stale.

  • Misreading typed dates and serial numbers

    Excel may store dates as serials; exported JSON often shows whatever the file stored. Verify date columns in the source app if ordering matters.

FAQ

Is my spreadsheet uploaded?

No. The file is read with FileReader inside your tab; clear the page when you are done on a shared machine.

Why did my file fail with a size error?

The tool caps inputs at 15 MB to keep typical browsers responsive. Export a smaller workbook, remove unused sheets, or split the data before converting.

How does this relate to CSV ↔ JSON?

Use XLSX here for native workbooks. If you already have comma- or tab-separated text, the CSV tool is faster and more predictable.

Common search terms

Phrases people search for that match this tool. See the full long-tail keyword index.

  • xlsx to json converter online
  • excel to json in browser
  • spreadsheet to json no upload

More tools

Related utilities you can open in another tab—mostly client-side.