Convert XLSX to JSON Excel Workbook ↔ JavaScript Object Notation Free Online Secure
Drop your XLSX file in and take away JSON. It is read and written here, in your browser, so the file never leaves your device — and what the crossing keeps, and what it cannot, is written out below rather than left for you to discover.
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Drop your XLSX file here, or choose one.
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Where these formats come from
CSV is the oldest and the least standardised: a table written as lines of text, in use since the 1970s and only described in writing in 2005, by which time every program had already decided for itself what the separator was and when to put quotation marks. XML grew out of SGML in 1998 for documents that must carry strict structure and be checked against a schema. JSON was pulled out of JavaScript by Douglas Crockford around 2001, deliberately stripped down to objects, arrays, numbers and strings — and that minimalism is why it took over the web. YAML is its readable cousin, where indentation does the work that brackets do elsewhere. The one thing that matters when converting between them: CSV is flat, a grid of rows and columns, while JSON, XML and YAML are trees.
Where you meet them
CSV is what a spreadsheet exports and what an accountant, a shop platform or a bank statement will hand you. JSON is what web services speak and what configuration files are increasingly written in. XML survives in older enterprise systems, in invoicing standards and inside the office formats themselves. YAML is where humans write settings by hand. Converting between them is the daily work of moving data from where it was produced to where it is needed.
Questions people ask
My CSV opened as one column in Excel. Why?
Because your spreadsheet expected a different separator. Excel follows the list separator of the computer's regional settings, which is a semicolon anywhere the comma is already the decimal mark — that is, most of continental Europe. A file separated by commas then looks like a single column of text. Use the import dialogue and state the separator explicitly, rather than double-clicking the file. The same regional setting is why 3.5 sometimes arrives as a date.
Why can't my nested JSON become a tidy spreadsheet?
Because a spreadsheet is flat and JSON is a tree. A row can hold one value per column; a JSON object can hold a list inside a field inside another list. Converting means choosing how to flatten that: either joining nested names into one long column heading, or repeating the parent row once for each child. Both are compromises, and neither can be undone automatically — which is why going back from the spreadsheet to the original shape usually needs a human decision.
Does the file lose quality?
It depends on what the two formats can hold. Converting between formats that store the same thing — a PNG to a BMP, a WAV to a FLAC — loses nothing. Converting into a format that throws information away to save space, such as JPEG or MP3, loses a little every time, and converting back does not bring it back. Where a choice exists, this page errs towards keeping the original quality rather than making the smallest file.
Is my file uploaded anywhere?
No. The conversion happens inside your browser, on your own machine; the file never leaves it and there is no server here that could receive it. That is why a large file is limited by your own memory rather than by an upload, and why nothing you convert can appear in anybody's logs — including ours. The audio and video tools do fetch their conversion engine from this site the first time you use them, some thirty megabytes once; after that the work still happens entirely on your machine.
Why people convert XLSX to JSON
An XLSX file is an Excel workbook, and for most people it is where their data lives: price lists, customer lists, schedules, results, catalogues. It is a fine place for people to keep and edit a table. But the moment that table has to feed a website, an app, a script, a chart library or a service with an API, the workbook is the wrong shape. Programs do not want to open Excel files. They want JSON, a plain structured text that every programming language reads directly. That is why people convert XLSX to JSON: they have the data in a spreadsheet, and the thing that will use it speaks JSON.
The situations are common. A developer with a product list kept by the sales team in Excel, which a web page should load. A teacher who has marks in a workbook and wants a script to process them. A shop owner who must upload a catalogue to a service that accepts only JSON. A researcher who wants to feed a table into an analysis tool. In every case the workbook is already tidy, and what is missing is only the change of language.
This page converts XLSX to JSON in your browser. Your file is read and written here, so it never leaves your device, which matters for customer lists, pupils' records and anything else personal. And the page tells you in advance what the crossing keeps and what it cannot, rather than leaving you to discover it. Below you will find how the conversion works, what happens with several sheets, what becomes of formulas and dates and what to prepare in the workbook.
How the conversion works
The first row gives the keys
Your workbook is read inside your browser. On each sheet, the first row is taken as the header, and its cells become the keys. Every other row becomes a record, an object in which each key is paired with the value in the same column. The result is a list of records, which is the shape that programs expect from a table.
One sheet gives an array, several give an object
One sheet gives an array. A workbook with several sheets gives an object keyed by sheet name, so nothing is dropped and nothing is quietly merged. If your workbook has sheets called Products and Prices, the JSON has a key Products holding its records and a key Prices holding its own. You can then take whichever you need.
Why sheets are kept apart
Sheets often hold different tables with different columns. Merging them would force a decision about how to line up unlike things. Keeping them apart, under their names, leaves that decision to you and to the program that reads the file.
What is kept
The cells
The cells are kept, with the first row as the keys. A sheet of 300 rows and 8 columns gives 300 records with 8 keys each.
The sheets and their names
Every sheet is carried over under its own name when there are several, so the structure of the workbook is visible in the JSON.
The values, with their types
Numbers arrive as numbers and text as text, because a workbook, unlike a CSV file, knows the difference. A column of amounts can be summed by the program that reads it, without any further interpretation.
What you should know before you convert XLSX to JSON
Formulas come across as values
A formula comes across as the value the spreadsheet last worked out, not as the formula. The file stores both, and only one of them is data. If a cell holds a sum, the JSON holds the result of the sum. This is almost always what you want for data exchange, since the receiving program has no use for a formula written for Excel.
Formatting is not data
Merged cells, colours, fonts, column widths and charts are not data either and do not cross. A merged cell is read as a single cell at its top-left position, and the cells it covers are empty. If your table relies on merged cells for headings, unmerge them before you convert XLSX to JSON.
Dates arrive as the workbook stored them
Dates arrive as the workbook stored them, which is not always the text you saw on screen. A workbook keeps a date as a number, counting days from a fixed starting point, and shows it formatted as you like. The JSON can therefore carry a number or a date value, depending on how the cell was stored, and not the text you saw. If you need a particular text format for dates, write the dates as text in the workbook first, or convert them in the program that reads the JSON.
How to convert XLSX to JSON here
Add your workbook
Drop the XLSX onto the page or pick it from your device. It is read inside your browser and is not uploaded.
Convert
Press the button. A workbook of ordinary size takes a moment. Leave the page open until it is done.
Download and check
Download the JSON and open it in a text editor. Look at the first record and the last, and check that the keys are the names you expect and that the values have the types you need.
A closer look at XLSX and JSON
Workbooks and trees
An XLSX is a package of sheets, each a grid of cells, with formatting, formulas and sometimes charts and pictures. JSON describes a tree of values. A grid with a header row is the simplest kind of tree, a list of records that share the same keys. So the conversion is straightforward in structure, and the interesting questions are about what to leave behind, which is why the rules above matter.
Why JSON is easier for programs
An Excel file is a complex format, readable only with a dedicated library. JSON has a strict grammar, a clear idea of strings, numbers, booleans and null, and ready-made readers in every programming language. A program that receives JSON needs no special library and no guesswork. That is why many services insist on it.
Size
JSON repeats the key names in every record, so the file can be larger than the table it came from, although an XLSX is itself compressed. For tables of thousands of rows, expect the JSON to be sizeable.
Common situations in detail
Feeding a web page or an app
A list of products, locations or events kept in a workbook can be converted to JSON and loaded by a page. You edit the sheet in the program you know, and let the page read the result.
Data for charts and maps
Chart and map libraries usually take JSON. Convert XLSX to JSON, point the library at the file and the chart draws itself from your table.
Uploads to services and APIs
Services that import catalogues, contacts or settings often accept JSON only. A workbook can be turned into the right file here, and uploaded.
Multi-sheet workbooks as a data package
A workbook with a sheet for products, another for categories and a third for prices becomes one JSON file with three keys. Applications can load the whole package at once.
Practical advice before you convert XLSX to JSON
Tidy the header row
Use short, clear, unique names in the first row of each sheet, without line breaks. The names become keys, and programs refer to keys by name.
Remove titles, notes and totals
A workbook often has a title above the table or a total row below. Delete them, or they will become records, and the keys may be wrong.
Unmerge cells
Merged cells confuse the reading of a table. Unmerge them and fill the values into each row where you can.
Paste values for formulas that matter
Formulas cross as their last calculated values. If the workbook has not been recalculated since a change, the stored values may be stale. Open it, let it recalculate and save before you convert XLSX to JSON.
Questions people ask before converting
Why are there several keys in the JSON?
Because the workbook has several sheets. A workbook with several gives an object keyed by sheet name.
Where are my formulas?
They crossed as the values the spreadsheet last worked out. The formula text itself is not data and does not come across.
Why do my dates look like numbers?
Because a workbook stores dates as numbers and formats them for display. Dates arrive as the workbook stored them. Convert them in the program that reads the JSON, or write them as text first.
What happens to colours and merged cells?
They do not cross. Colours, fonts, column widths, merged cells and charts are formatting and not data.
Is my file uploaded?
No. The conversion runs in your browser and the file never leaves your device.
Can I go back to a workbook?
Yes. JSON to XLSX turns a list of records back into a worksheet.
Choosing wisely when you convert XLSX to JSON
JSON or CSV?
If the receiving program reads plain tables, a CSV may do. JSON to CSV and CSV to JSON work with text files. JSON is better when you need typed values and several sheets in one file.
Other targets
If the destination is a markup file or a configuration, JSON to XML and JSON to YAML can follow.
Keep the workbook
The workbook is the master for people who maintain the data. Keep it, and convert again when it changes.
Getting a good result after the conversion
Validate the JSON in a viewer
Open the result in an editor that understands JSON and collapse the records. If the structure looks like what you expect, it is sound.
Compare a few records with the source
Take a few rows in the middle and check them against the sheet. It takes a minute and tells you the conversion is faithful.
Minify for publishing
If the file will be loaded by a web page and is large, tools exist that remove whitespace and make it lighter. The data stays the same.
Preparing your workbook so that it converts well
Keep each sheet to one table
When you convert XLSX to JSON, each sheet should hold a single table starting at the top left, with the header in the first row. Side-by-side tables or notes in the margin will be read as extra columns.
Keep each column to one kind of thing
A column that holds numbers in most rows and words in a few will produce a mixture of types. Clean the odd ones so that each column means one thing.
Name the sheets meaningfully
The names of the sheets become keys when there are several. Products and Prices are better than Sheet1 and Sheet2, and your program will be easier to read.
Test with a small piece first
If the workbook is large, copy the first twenty rows into a test file and convert that. A quick look at the result shows whether the keys and types are what you expect.
Using the result after you convert XLSX to JSON
Reading a multi-sheet file
When the workbook had several sheets, the JSON is an object, and each sheet is one of its keys. A program picks the sheet it needs by name. If you convert XLSX to JSON for a page that shows only the price list, it reads the Prices key and ignores the rest.
Loading it in a web page
A page can fetch the file and turn it into a list, a table or a set of markers on a map with a few lines of script. Because the file is plain text, you can host it beside the page, and a change to the data needs only a new conversion and a new upload.
Empty cells
An empty cell arrives as an empty value for its key. Programs differ in how they treat that: some see an empty string, some see nothing. If it matters, decide in the program how to read blanks.
Large workbooks
A workbook with many thousands of rows gives a large file. If a page must load it, consider splitting the data into pages, or loading only the part that is needed, so that visitors are not made to wait.
Keep the workflow simple
The easiest routine is to keep the workbook as the single source of truth, and to convert XLSX to JSON each time it changes. Editing the JSON by hand leads to a version that no longer matches the sheet, and the next conversion overwrites your edits.
Privacy and handling
Why local conversion matters for data
Workbooks often hold what is private: customers, pupils, addresses, prices. Many online converters upload your file to a server, process it and send back the result, and for a while a copy lives on a machine you do not control. Here your own browser does the work, so the data stays on your device.
What happens when you leave
When you close the page, the converted file disappears from the browser, so download it first. Nothing about your data is kept.
If something goes wrong
The keys are wrong
The first row was not the header. Remove any title or blank lines above the table and convert again.
Some cells are empty that should not be
They may have been part of a merged cell. Unmerge and fill them in the workbook first.
The page freezes with a large workbook
Everything runs on your device, and a large workbook needs memory. Try again on a computer, or save only the sheet you need.
Related tools
The same family of tools covers the neighbouring jobs. To go back, use JSON to XLSX. For plain tables, CSV to JSON and JSON to CSV work with text files. For older and open spreadsheets, XLS to ODS and ODS to XLS move tables between formats. For other formats of structured data, there are JSON to XML and JSON to YAML.
A worked example
Say your sales team keeps a workbook with two sheets, Products and Prices, and the website should show both. You drop the XLSX here and press the button. A moment later you download one JSON file with two keys, Products and Prices, each holding its list of records. The prices are numbers, because they were numbers in the sheet. You place the file beside the page, and the script reads it. When a price changes, the team edits the workbook and you convert again.
A short checklist
Before converting
Put the header in the first row of each sheet. Remove titles, notes and totals. Unmerge cells. Recalculate and save.
While converting
Stay on the page until the file is ready.
After converting
Open the JSON, check the keys and a few records, and keep the workbook as your master.
Common mistakes
Leaving a title above the header
The first row becomes the keys. A title there ruins them.
Expecting formulas
Formulas cross as their last calculated values. The JSON holds data, not calculations.
Deleting the workbook
Keep it. It is the version you can edit in a spreadsheet.
Your data stays on your device
The conversion happens locally. Your workbook is read by your own browser, rewritten there and handed back as JSON. Nothing is uploaded, so no copy ends up on a server and nobody else can read it. For data with private content, that is the safe way to convert XLSX to JSON.
Summary
To convert XLSX to JSON here, drop the workbook and press the button. It is read and written in your browser, so the file never leaves your device. The cells are kept, with the first row as the keys. One sheet gives an array, and a workbook with several gives an object keyed by sheet name, so nothing is dropped and nothing is quietly merged. A formula comes across as the value the spreadsheet last worked out, not as the formula. Merged cells, colours, fonts, column widths and charts are not data either and do not cross. Dates arrive as the workbook stored them, which is not always the text you saw on screen.