Why does switching between sheets take a moment instead of being instant?

Switching sheets re-runs the conversion from scratch rather than swapping between sheets already held in memory. For most spreadsheets that's not noticeable, but a very large workbook with many sheets will re-parse each time you switch.

Can I drop a .csv or .ods file here too, not just .xlsx or .xls?

Yes. The underlying library (SheetJS) reads OpenDocument spreadsheets and CSV files the same way it reads Excel workbooks, and the file picker accepts all four extensions even though the page focuses on Excel in its name.

What happens if my browser can't create the Web Worker, for example because of a restrictive extension?

The conversion fails with a clear "Worker unavailable" message rather than hanging or silently doing nothing. Nothing partially processes; either the worker starts and handles the file, or you get an explicit error.

Excel to JSON Converter: Upload .xlsx & Get JSON Free

Drop your Excel file here

or click to browse · .xlsx, .xls, .ods

JSON Output

Headers

JSON output will appear here…

Parsed in an isolated Web Worker: no file is uploaded to servers

Excel to JSON: bridging spreadsheets and code

Excel remains the default tool for data collection, financial modeling, and reporting across most organisations. But applications and APIs don't speak .xlsx.

Converting Excel to JSON lets you load spreadsheet data into a JavaScript app, seed a database, or pass it to a REST endpoint, all without writing a parser or installing a library.

Multi-sheet support and header detection

Real-world Excel files often contain multiple sheets: a summary tab, regional breakdowns, monthly data. The converter lists every sheet and lets you switch between them instantly.

Enable "Headers" to use the first row as JSON object keys; disable it to get arrays of raw values per row. Files are parsed entirely in your browser using the SheetJS library.

Data migration and integration use cases

Finance teams export budget spreadsheets to JSON to feed a dashboard or planning tool. Operations teams convert inventory .xlsx files into JSON for database seeding.

Analysts share clean JSON with developers who need structured data without spreadsheet tooling. Because no file is uploaded to a server, sensitive financial or HR data stays private.

Frequently asked questions

Processing is capped at 30 seconds. If it runs longer than that, the worker handling the file is terminated and a timeout error is shown, rather than leaving the page hanging with no explanation.

Excel → JSON

Excel to JSON: bridging spreadsheets and code

Multi-sheet support and header detection

Data migration and integration use cases

Frequently asked questions