Excel to JSON Converter
Convert Excel workbooks (.xlsx, .xls) into clean JSON data structures instantly. Everything runs locally in your browser so your confidential spreadsheets never touch an external server.
How to use
Click Select Excel File or drop your .xlsx workbook into the dropzone, or click Try an example.
If your workbook contains multiple sheets, choose the specific sheet you want to convert.
Select your preferred output format and toggle unflattening for nested dot-notation keys.
Copy the generated JSON to your clipboard or download it as a .json file.
Why convert Excel spreadsheets into JSON?
Microsoft Excel (.xlsx) is the global standard for business reporting, inventory logs, financial records, and operational spreadsheets. However, modern web applications, microservices, and databases communicate through JavaScript Object Notation (JSON). Manually re-entering data or exporting to intermediate formats often results in formatting errors or loss of structured types. An in-browser Excel to JSON converter allows software engineers and data analysts to convert binary workbooks into clean, programmatic payloads in seconds without writing custom parsing scripts.
Multi-sheet workbook support and selective export
Enterprise Excel workbooks commonly organize distinct departments or reporting periods into multiple tabbed worksheets. This converter automatically parses workbook metadata to identify every available sheet. You can seamlessly switch between worksheets using the sheet dropdown to inspect and export individual tables without splitting or modifying your original spreadsheet file. Each sheet is isolated, giving you granular control over exactly which data tables are converted into JSON.
Accurate date serialization and numeric precision
One of the most persistent frustrations when exporting Excel spreadsheets is date corruption. Excel stores dates internally as serial numbers offset from the year 1900, which many naive parsers render as ambiguous raw integers (such as 45687). This converter leverages date parsing to detect cell timestamps accurately, converting them into universal ISO 8601 calendar strings (YYYY-MM-DD). Floating-point values, percentages, and booleans are likewise mapped directly to their native JavaScript equivalents rather than coerced into plain strings, preserving data integrity.
Rebuilding nested object structures
Tabular layouts cannot represent complex tree structures directly, so engineers often use dot-notated column names such as customer.address.city or item.dimensions.weight. With Unflatten keys enabled, the parser dynamically resolves these dot paths into deeply nested JSON objects, eliminating the need for custom transformation steps before ingestion into MongoDB or REST APIs.
Complete local privacy guarantee
Spreadsheet files regularly contain financial balances, proprietary pricing matrices, customer rosters, and confidential corporate data. Unlike conventional online tools that upload your files to remote cloud servers, this tool executes 100% in your local web browser. Your binary files are parsed locally using WebAssembly and client-side memory, ensuring your proprietary records never touch an external server or leave your machine.
Frequently asked questions
Does this tool upload my Excel spreadsheets to any server?
No. The entire file reading, decompression, and JSON parsing process executes locally inside your web browser. No network requests are made with your file data.
Which Excel file formats are supported?
The converter supports modern OpenXML workbooks (.xlsx) and legacy spreadsheet files (.xls).
How does the tool handle formulas in cells?
The parser extracts the calculated cached values computed by Excel, ensuring your JSON accurately reflects the spreadsheet results rather than raw formula text.
Can I choose which sheet to convert if my workbook has multiple tabs?
Yes. When you load a multi-sheet workbook, a sheet selector dropdown automatically appears allowing you to convert any sheet.
What output formats are available?
You can output standard Array of Objects (each row as a JSON object), Array of Arrays (a raw 2D grid), or a Keyed Object indexed by the first column values.