YYTOOLS / THE EVERYDAY TOOLBOX
CSV to JSON
Convert CSV to JSON while preserving leading zeros and long numbers.
Processed locally · No upload · No sign-up
Add your data. Make it useful.
Choose a file or paste text. Your data stays in this browser.
Up to 5,000 data rows, 200 columns and 100,000 data cells. Input: 0 / 2,000,000 characters. Files must use UTF-8.
How to use
- Choose a file or paste data. For Excel, select a worksheet.
- Adjust options, run the tool, then check the preview or error message.
- Review row and column counts, then copy or download the complete result. Run again after editing input.
The first row defines field names. CSV values stay strings to preserve leading zeros and long numbers. Short rows are padded. Duplicate or blank headers and overly wide rows raise errors.
Previews show up to 50 rows; downloads contain all results. Limits: 5,000 data rows, 200 columns, 100,000 data cells and 5 MiB per file. Combined exported text and text read from Excel are limited to 10,000,000 characters. Exceeding a limit raises an error; data is truncated only when "Truncate long cells" is enabled, with a count shown.