About this tool
Why it exists.
Spreadsheets are for people, while CSV and JSON are for programs. Moving data between them is a daily task for analysts, developers and anyone importing data into another system.
Open an .xlsx workbook, pick a sheet and choose CSV or JSON. Or paste CSV or JSON and download a new Excel file. The conversion uses the values stored in your file, so formulas appear as their last calculated results. Everything runs in your browser.
How to use it.
- Choose Excel → CSV / JSON or the reverse.
- Open your file or paste your data.
- Download the converted file.
Good questions.
Does it support old .xls files?
No. It reads modern .xlsx workbooks. Open an .xls file in Excel and save it as .xlsx or CSV first.
What happens to formulas and formatting?
Formulas are converted to their last calculated values. Colours, fonts, charts, images and macros are not included.
How are dates handled?
Cells formatted as dates are written as text such as 2026-03-15, which most systems can read.