Excel to JSON Converter
Convert Excel XLSX/XLS files to JSON arrays instantly in your browser. SheetJS powered, no upload, no server. Proper type handling.
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Compatible con: .xlsx, .xls, .csv · Máx: 50MB
📘 Cómo usar
Guía disponible en inglés. Traducción automática próximamente.
How to Convert Excel to JSON
What This Tool Does
The Excel to JSON Converter reads .xlsx, .xls and .csv spreadsheet files and transforms them into structured JSON arrays using SheetJS. Each row becomes a JSON object, with column headers as keys (when "First row is header" is enabled). All processing happens in your browser — no file upload.
Why Browser-Based Conversion Matters
Spreadsheet files often contain business data: customer lists, financial reports, product catalogs, inventory exports. Uploading these to an online converter means sending sensitive business data to an unknown server. This tool uses SheetJS (the community edition) running in a Web Worker to parse and transform the data locally. Your spreadsheet never leaves your browser.
How to Use
- Drop your .xlsx, .xls, or .csv file onto the upload zone (max 50MB).
- Choose the sheet index if your workbook has multiple sheets (0 = first sheet).
- Keep "First row is header: yes" if your data has column names in row 1. The converter uses these as JSON keys. Set to "no" for headerless data, and keys will be generated as column_0, column_1, etc.
- Click Convert. The JSON output appears in the preview area.
- Copy or download the .json file.
Type Handling
SheetJS automatically detects cell types: numbers are emitted as JSON numbers, dates as ISO date strings, booleans as true/false, and text as strings. Empty cells become null. This means your JSON output has proper types without manual post-processing.
Multi-Sheet Workbooks
If your workbook has multiple sheets, use the sheet index option to select which sheet to convert. Index 0 is the first sheet, 1 is the second, and so on. To convert all sheets, run the tool once per sheet with a different index.
Privacy and Limits
Parsing uses SheetJS running in a Web Worker. Your file is read as an ArrayBuffer, parsed, and transformed — all locally. Files up to 50MB are supported. Very large spreadsheets (100K+ rows) may take a few seconds but will complete in the worker without freezing the UI.
❓ Preguntas frecuentes
Which Excel formats are supported?
XLSX (Excel 2007+), XLS (Excel 97-2003), and CSV. SheetJS handles all three with automatic format detection.
How are dates and numbers handled?
SheetJS auto-detects cell types. Numbers become JSON numbers, dates become ISO strings, booleans become true/false, and empty cells become null.
Can I convert a specific sheet from a multi-sheet workbook?
Yes. Use the "Sheet index" option. Index 0 is the first sheet, 1 is the second, and so on.
Is my spreadsheet uploaded to a server?
No. SheetJS runs in a Web Worker in your browser. Your file never leaves your device, making this safe for confidential business data.