How it works
- Drop your spreadsheets or CSV files.
- Choose the direction and output options.
- Download the converted files.
Why use it
- Numbers detected.
- Leading zeros kept.
- JSON input.
- Bulk.
Questions and answers
Why did Excel change my numbers?
Opening a CSV directly makes Excel guess types. A real XLSX avoids that.
Can I merge sheets?
Each file becomes a workbook with one sheet.
Related guides
CSV, Excel or JSON: which format for your data?
We saved the same 100,000 row table as CSV, as an Excel workbook and as JSON, then compared the sizes, how fast each one reads in code, and what goes wrong with dates, leading zeros and long numbers.