Spreadsheet Converter

Convert between CSV, XLSX, and JSON formats with customizable options. High-quality conversion with live preview and multiple format support.

Overview

Spreadsheet Converter lets you convert files between CSV, Excel (XLSX/XLS), and JSON in any combination — CSV to JSON, XLSX to CSV, JSON to XLSX, and every other pairing — directly in your browser. Auto-detection handles CSV delimiters so you can drop in files exported from any tool without adjusting settings. Because processing runs locally via JavaScript and never touches a server, sensitive business data, personal records, or confidential exports stay entirely on your device. A live preview shows the reformatted data before you download, so you can catch structural issues — like nested JSON fields being flattened to dot-notation columns — before committing to the file.

Key Features

  • Convert between CSV, XLSX, and JSON
  • Multiple output format options
  • Customizable delimiters and structure
  • Live preview before conversion
  • Support for large files
  • Auto-detect CSV delimiters

Common Use Cases

  • CSV to JSON for Developers — Developers convert exported CSV datasets — from databases, analytics tools, or CRMs — into JSON arrays or arrays-of-objects ready for ingestion by an API or application.
  • Excel to CSV for Data Pipelines — Data analysts strip XLSX files down to plain CSV so they can pipe records into pandas, dbt, or any CLI tool that expects delimiter-separated input.
  • JSON to Excel for Reporting — Product or operations teams take JSON API responses and convert them to XLSX for sharing pivot-table-ready reports with stakeholders who work in Excel.
  • Privacy-Sensitive Record Conversion — HR teams and finance staff convert payroll or compliance spreadsheets without risking exposure — files never leave the browser so no data is transmitted to any server.
  • Delimiter Normalization — Users reconcile semicolon-delimited European CSV exports against comma-delimited files by re-exporting to a consistent delimiter or to XLSX before merging datasets.

How It Works
1

Upload Your File

Select your CSV, XLSX, or JSON file. The tool automatically detects the format and structure of your data for optimal conversion.

2

Choose Output Format

Select your desired output format (CSV, XLSX, or JSON) and customize conversion options like delimiters, JSON structure, or Excel formatting.

3

Preview & Download

Review the converted data in the live preview to ensure accuracy, then download your file in the new format instantly.

Frequently Asked Questions

What file formats can I convert between?
You can convert between CSV, Excel (XLSX/XLS), and JSON formats in any direction. For example: CSV to JSON, XLSX to CSV, JSON to XLSX, and all other combinations.

How does the tool handle different data structures?
The converter intelligently adapts to your data structure. CSV and Excel data become array of objects in JSON, while JSON arrays can be converted to tabular CSV/Excel format with automatic column detection.

Can I customize the conversion options?
Yes, you can customize CSV delimiters (comma, semicolon, tab, pipe), JSON output structure (array of objects or arrays), and Excel formatting options to match your specific needs.

What happens to complex data during conversion?
Nested JSON objects are flattened using dot notation for CSV/Excel conversion. Excel formulas are converted to their calculated values. Data types are preserved as much as possible across formats.

Is there a preview before downloading?
Yes, the tool provides a live preview showing exactly how your data will look in the target format. This allows you to verify the conversion before downloading.

Are there any file size limitations?
The tool can handle files up to 50MB efficiently. For larger datasets, consider splitting your data into smaller files before conversion.

How is data privacy maintained?
All conversions happen entirely in your browser. Your files are never uploaded to our servers, ensuring complete privacy and security of your data.

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