CSV / JSON to Excel

Convert CSV and JSON to Professional Excel Workbooks

Raw CSV files and JSON data are powerful but lack the structure and formatting of a proper Excel workbook. This tool transforms one or more CSV or JSON files into a polished .xlsx file with each source file occupying its own sheet. Column widths are automatically sized to fit your content, and you can optionally apply bold formatting with a shaded background to the header row for a professional appearance.

How It Works

• Multiple files — Upload several CSV or JSON files at once. Each file becomes a separate sheet in the output workbook, named after the source filename. This is perfect for combining related datasets into a single organized workbook.
• CSV parsing — Handles standard comma-separated values with proper UTF-8-BOM detection. Numeric values embedded in strings are automatically converted to numbers when safe to do so, preserving their type for Excel calculations and formulas.
• JSON support — Accepts arrays of objects where each key becomes a column, and arrays of arrays which are preserved as-is. When processing objects, all unique keys across every object are collected to form the complete column set, ensuring no data is lost.

Use Cases

This tool is ideal for data analysts who receive CSV exports from databases and need to present them in a formatted workbook, developers converting JSON API responses into readable spreadsheets for non-technical stakeholders, and anyone who needs to combine multiple flat files into a single organized Excel document. The auto-sizing feature ensures columns are wide enough to display your data without truncation. The bold header option makes the output ready for presentation without additional formatting work in Excel.