LOCAL DATA CONVERTER / XLSX TO JSON

Excel to JSON

Export one XLSX worksheet as a formatted JSON record array using its first row as stable property names and stored cell results as values.

Processed in this browserOne unencrypted .xlsx file up to 15 MB and 50 worksheets. The selected sheet is limited to 50,001 rows including its header, 200 columns, 1,000,000 cells, and 20 MB JSON output.

Step 1 / source

Choose the source

XLSX - 50,000 records

Drop one file here

Choose a modern workbook whose first row contains the property names you want in JSON.

Browse filesChecking publication status...

No file upload

This operation runs with browser APIs. Nirmion receives catalogue requests, not the selected source bytes.

Original stays unchanged

The converter creates a separately named output. It never writes back into the source file.

Bounded work

One unencrypted .xlsx file up to 15 MB and 50 worksheets. The selected sheet is limited to 50,001 rows including its header, 200 columns, 1,000,000 cells, and 20 MB JSON output.

Plain-language method

How worksheet rows become JSON objects

Nirmion reads one selected worksheet, normalizes blank or duplicate header cells into unique property names, uses stored formula results without recalculation, skips fully empty rows, and serializes strings, numbers, booleans, dates, and empty cells into a separate JSON array.

01
Choose a valid source
Put property names in row one and keep one logical record per later row. Hidden rows, styles, charts, comments, and merged layout do not define JSON data.
02
Review the conversion choices
Choose the worksheet by its one-based tab position. Omit removes properties for empty cells; Null keeps those properties with an explicit null value.
03
Inspect the separate result
The output filename includes the cleaned worksheet name and ends in .json. It is UTF-8, two-space formatted, and contains no workbook styling.

Useful when

Practical jobs this tool handles

Turn an approved spreadsheet table into API seed data.
Export a worksheet for a web or automation workflow.
Create reviewable JSON without copying rows manually.

Before converting

Make the header unambiguous

Use a clear first-row header for every populated column.
Select the correct worksheet number from tab order.
Check dates and stored formula results in the JSON output.

Know the boundary

Workbook presentation is not data

Charts, images, formulas, comments, colours, merged cells, and macros are not represented. Formula cells contribute only a stored result when the workbook contains one.

Quick answers

Questions before you convert

One-sheet export keeps the transformation inspectable.

Does it recalculate formulas?

No. The browser never executes workbook formulas; it uses the stored result when available.

How are duplicate headers handled?

Later duplicates receive a numeric suffix so one value cannot overwrite another.

Can it export every sheet at once?

Not on this route. Select one sheet so its JSON schema remains clear.