Tablizer

Convert Excel to JSON Online

Drop an Excel workbook and get JSON. The file is read in your browser, so a spreadsheet you would not upload to a random converter never leaves your machine.

From

The only part of this site that uses a server. The address is sent to it so the page can be fetched, because a browser is not allowed to fetch someone else's page itself. Your own files are never involved.

Nothing here is uploaded. The parsing happens on this page.
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Paste or upload something above and it will appear here.
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The output will appear here once there is a table to convert.

What Excel is

An Excel workbook is a zip archive of XML parts describing sheets, cells, formulas, styles and charts. The .xlsx extension is that format; .xls is the older binary one from before 2007.

Finance, operations and anyone who received a file from finance or operations.

What JSON is

JSON is a text format for nested data: objects with named keys, arrays, strings, numbers, booleans and null. It has no date type and no comments.

Every web API, most configuration files and anything that talks to JavaScript.

What changes when you convert Excel to JSON

Only the first sheet is read, and cells are read as the text Excel displays rather than the number underneath. That matters for dates: a cell showing 15/03/2026 arrives as that string, not as a serial number you would then have to decode.

You choose the shape. An array of objects is the default and the one most code expects. A 2D array is smaller. Column arrays suit charting libraries. A keyed object suits lookups by id.

The first sheet becomes the records. Header cells become keys and each row becomes an object.

Values arrive as the text Excel was displaying, which keeps dates readable rather than turning them into serial numbers. Turn type inference on if you want numbers and booleans in the JSON.

Formulas are already resolved. What you get is the value that was on screen, not the expression that produced it.

What carries over from Excel to JSON

Excel records 2 things about a table that JSON has no way to hold.

JSON has no header row. The column names are repeated as keys on every record instead, which is why the result is bigger on disk than the table it came from.

Anything visual in the Excel - weight, alignment, colour, column widths - has no counterpart in JSON and is dropped. The values are what survives.

Both formats record types, so numbers, booleans and nulls survive as themselves rather than as text.

A worked example

Three rows of staff data, with an identifier that has a leading zero, a value containing a comma, a value containing quotes and one blank cell. Those are the four places formats disagree, so they are the four places to look.

Excel in
id,name,role,started,hours
007,Halima Yusuf,"Analyst, data",2024-03-15,38.5
012,"Jonah ""Jo"" Pryce",Engineer,2025-11-02,
104,Wei Chen,Manager,2023-06-30,40
JSON out
{
  "staff": [
    {
      "id": "007",
      "name": "Halima Yusuf",
      "role": "Analyst, data",
      "started": "2024-03-15",
      "hours": "38.5"
    },
    {
      "id": "012",
      "name": "Jonah \"Jo\" Pryce",
      "role": "Engineer",
      "started": "2025-11-02",
      "hours": ""
    },
    {
      "id": "104",
      "name": "Wei Chen",
      "role": "Manager",
      "started": "2023-06-30",
      "hours": "40"
    }
  ]
}

Questions

How do I convert Excel to JSON?

Paste your Excel into the box above or drop the file onto it. Check the table in the grid, then copy or download the JSON from the output panel. It takes one step and the data never leaves your browser.

Does converting to Excel keep my formulas?

No. A table has values, not formulas. If your source came from Excel in the first place, the formulas were already resolved to their results before they reached this page. Anything that was =SUM(A1:A10) arrives as the number it produced.

Why did my zip code lose its leading zero?

Type inference turned the text 07030 into the number 7030. Tablizer leaves inference off by default for exactly this reason, and refuses to convert any value starting with a zero followed by a digit even when it is on.

Is there a limit on file size?

No. The work happens on your own machine, so the limit is your machine's memory rather than an upload cap. A file with tens of thousands of rows converts in a second or two.

Is my data uploaded anywhere?

No. The parsing and generating are done by JavaScript running on this page. You can watch the network tab while you convert and see that nothing is sent.

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