Convert XLSX to JSON Online Free

Extract data from Excel spreadsheets as structured JSON. Each row becomes a JSON object with column headers as keys. Perfect for APIs, databases, and web applications.

By ChangeThisFile Team · Last updated: March 2026

Quick Answer

ChangeThisFile converts your Excel spreadsheet to structured JSON directly in your browser using the SheetJS library. Headers become keys and each row becomes a JSON object, ready for APIs and databases. Your file stays on your device for complete privacy. Free, instant, no signup required.

Free No signup required Files stay on your device Instant conversion Updated March 2026

Convert XLSX to JSON

Drop your XLSX file here to convert it instantly

Drag & drop your .xlsx file here, or click to browse

Convert to JSON instantly

XLSX vs JSON: Format Comparison

Key differences between the two formats

Feature	XLSX	JSON
Format type	Binary spreadsheet (ZIP of XML)	Plain text data format
Data access	Requires Excel or library	Native in all programming languages
Data types	Excel types (dates, formulas, numbers)	String, number, boolean, null
Structure	Rows, columns, multiple sheets	Nested objects and arrays
File size	Larger with formatting overhead	Compact, data only
API compatibility	Not directly usable	Universal standard for web APIs
Human editing	Spreadsheet application required	Any text editor

When to Convert

Common scenarios where this conversion is useful

API data preparation

Convert Excel data to JSON for sending to REST APIs. Each spreadsheet row becomes a JSON object ready for POST requests or batch operations.

Web application data loading

Load spreadsheet data into JavaScript applications. JSON is natively parsed by browsers, making it ideal for client-side data display and manipulation.

NoSQL database seeding

Import spreadsheet data into MongoDB, Firebase, or CouchDB. JSON maps directly to document database records.

Data migration and ETL

Convert Excel reports to JSON as the first step in data migration pipelines. JSON is easier to transform, filter, and validate programmatically.

Who Uses This Conversion

Tailored guidance for different workflows

Office Workers

Convert XLSX documents to JSON for sharing with colleagues who use different software
Transform XLSX reports to JSON for archiving or distribution to external stakeholders

Review the converted JSON for formatting changes, especially tables, headers, and page breaks

Convert to JSON as the final step after all edits are complete to avoid formatting drift

Students

Convert XLSX lecture notes to JSON for submitting assignments in the required format
Transform XLSX study materials to JSON for reading on tablets or e-readers

Double-check that fonts and special characters render correctly in the converted JSON file

Save a backup of your XLSX original before converting, in case you need to make edits later

Professionals

Convert XLSX contracts or proposals to JSON for secure, read-only distribution to clients
Transform XLSX templates to JSON for use across different office suites and platforms

Verify that hyperlinks and cross-references still work after converting XLSX to JSON

For legally sensitive documents, confirm the JSON output matches the XLSX layout exactly

How to Convert XLSX to JSON

1

Upload your Excel file

Drag and drop your .xlsx file onto the converter, or click to browse. The first sheet in the workbook is converted.
2

Automatic conversion

Column headers become JSON object keys. Each data row becomes a JSON object. Numbers, dates, and text are typed appropriately.
3

Download the JSON result

Click Download to save your .json file. The output is an array of objects, pretty-printed with 2-space indentation.

Frequently Asked Questions

How are column headers used?

The first row of your spreadsheet becomes the JSON property names (keys). Each subsequent row creates a JSON object with those keys and the row's values.

What about Excel formulas?

Formulas are resolved to their last computed values. The JSON output contains the calculated results, not the formula expressions.

How are Excel dates converted?

Excel dates are converted to their text representation based on the cell format. ISO 8601 format (YYYY-MM-DD) is used when the original format is ambiguous.

Which sheet is converted?

The first (leftmost) sheet in the workbook is converted. If you need a different sheet, rearrange the order in Excel before converting.

How are empty cells handled?

Empty cells are omitted from the JSON objects. Each object only contains keys for cells that have values.

Are number types preserved?

Yes. Numeric cells become JSON numbers, not strings. This includes integers and decimals. Cells formatted as text remain strings.

Can I convert files with thousands of rows?

Yes. The converter handles large spreadsheets. Performance depends on your device's memory, but files with hundreds of thousands of rows work well.

Do I need Excel installed?

No. The converter uses SheetJS to parse Excel files directly in the browser. No Office installation is needed.

Can I convert password-protected files?

No. Password-protected Excel files cannot be parsed in the browser. Remove the password in Excel before converting.

Is my spreadsheet data private?

Yes. The conversion runs entirely in your browser. No data is sent to any server. Safe for confidential business data.

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Need to convert programmatically?

Use the ChangeThisFile API to convert XLSX to JSON in your app. No rate limits, up to 500MB files, simple REST endpoint.

View API Docs

Read our guides on file formats and conversion

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