Which row is used for the keys?

The first row with anything in it, so a blank row or two above the table is skipped. Each column's header becomes the key; a column with no header is called column1, column2 and so on, and a repeated header gets _2, _3 added so no value is lost.

How do I get nested JSON from a flat sheet?

Name the columns with dots, such as address.street and address.city, and keep "Dotted headers as nested objects" ticked: each row then has an address object holding street and city. This is the reverse of what JSON to Excel does, so a sheet made there comes back to the same shape.

How are dates written in the JSON?

As ISO 8601 text: 2024-05-01 for a date, 2024-05-01T09:30:00 for a date with a time, and 09:30:00 for a time on its own. A date typed as text in the sheet stays as that text.

What happens with several sheets?

With All sheets ticked, the JSON is an object whose keys are the sheet names, each holding that sheet's rows; empty sheets are left out. Untick it to get just the first sheet as a plain array. A workbook with one sheet always gives an array.

Does a CSV keep codes like 00123?

Yes. A CSV is read as text, then plain numbers and true/false get their JSON types back, so 42 becomes a number while 00123 and +44 20 7946 0000 stay text.

Does my workbook leave my computer?

No. The file is read and the JSON written in this browser tab on your device. Password-protected workbooks cannot be read; remove the password in Excel, or with Unprotect Excel, first.

Stays on your computer How this works

Free Excel to JSON converter

Turn an Excel spreadsheet (.xlsx, .xls, .ods or CSV) into JSON: the header row becomes the keys, each row an object, dates ISO text, numbers numbers, and dotted headers nested objects if you like. Converted in your browser; nothing is uploaded.

Dotted headers (address.city) as nested objects All sheets Empty cells as null Indented

Drop an Excel file here, or click to chooseTap to choose an Excel file.xlsx, .xls, .xlsm, .xlsb, .ods or .csv · up to 100 MB · nothing is uploaded

About this Excel to JSON converter

Developers and no-code builders often get their data as a spreadsheet: a product list, translations, a price table, test data, a content calendar. This page turns it into the JSON an app, an API or a static site wants: an array of objects, one per row, with the header row as the keys. A workbook with several sheets becomes one object with an array per sheet. It is free to use, with no account and no upload limit, and it runs entirely in your browser: nothing is uploaded, and while the page stays open, a feature you have already used keeps working offline.

The workbook is read by SheetJS, the same reader as the site's Excel Viewer. Cell values keep their types: numbers stay numbers, TRUE/FALSE become true/false, and dates (which Excel stores as numbers) become ISO text such as 2024-05-01, read from the cell's calendar date so no time zone can shift them. Formulas give their saved results; none is calculated.

What you can do

Convert .xlsx, .xlsm, .xlsb, .xls, .ods and .csv files to JSON
The header row as keys, blank headers named column1, column2…, repeated headers made distinct
Headers such as address.city as nested objects (can be turned off)
All sheets as one object by sheet name, or just the first sheet as an array
Dates as ISO text, numbers and true/false with their JSON types
Empty cells left out, or written as null
Indented or compact JSON; save it as a .json file or copy it

How to convert Excel to JSON

Drop the spreadsheet on the box, or click to choose it.
Tap the box and choose the spreadsheet.
Choose the options; the JSON below updates at once.
Press Save JSON, or Copy JSON to paste it into your code.

Questions

Which row is used for the keys?: The first row with anything in it, so a blank row or two above the table is skipped. Each column's header becomes the key; a column with no header is called column1, column2 and so on, and a repeated header gets _2, _3 added so no value is lost.
How do I get nested JSON from a flat sheet?: Name the columns with dots, such as address.street and address.city, and keep "Dotted headers as nested objects" ticked: each row then has an address object holding street and city. This is the reverse of what JSON to Excel does, so a sheet made there comes back to the same shape.
How are dates written in the JSON?: As ISO 8601 text: 2024-05-01 for a date, 2024-05-01T09:30:00 for a date with a time, and 09:30:00 for a time on its own. A date typed as text in the sheet stays as that text.
What happens with several sheets?: With All sheets ticked, the JSON is an object whose keys are the sheet names, each holding that sheet's rows; empty sheets are left out. Untick it to get just the first sheet as a plain array. A workbook with one sheet always gives an array.
Does a CSV keep codes like 00123?: Yes. A CSV is read as text, then plain numbers and true/false get their JSON types back, so 42 becomes a number while 00123 and +44 20 7946 0000 stay text.
Does my workbook leave my computer?: No. The file is read and the JSON written in this browser tab on your device. Password-protected workbooks cannot be read; remove the password in Excel, or with Unprotect Excel, first.

To check or tidy the JSON, use the JSON Toolkit. For the opposite direction there is JSON to Excel, plus JSON to CSV and XML to Excel.