Excel converter
Open .xlsx, .xls or .csv and export any sheet to CSV, JSON or PDF — and turn a CSV back into a real .xlsx. Fully offline.
Open Excel converter →What is the Excel converter?
A free, fully offline spreadsheet converter that opens .xlsx, .xls or .csv files in your browser, lists every sheet and previews the active one. You can export any sheet — or all sheets — to CSV, JSON or PDF, and turn a CSV back into a real .xlsx workbook. Your files are read on your device and never uploaded.
How to use Excel converter
- Open a spreadsheet — Drop an .xlsx, .xls or .csv file onto the page or click to browse. Everything stays in your browser.
- Pick a sheet — Use the Sheet selector to choose which sheet to work with; a preview of its rows appears below.
- Choose all sheets if needed — Tick All sheets if you want the export to cover every sheet in the workbook rather than just the active one.
- Export the format you need — Download the data as a CSV spreadsheet, a JSON file or a PDF document. If you opened a CSV, you can also export it as an XLSX workbook.
Frequently asked questions
Are my spreadsheets uploaded?
No. The converter reads and exports everything in your browser, so the contents of your files never leave your device. It also works offline once loaded.
Which file types can I open?
It opens .xlsx, .xls and .csv files. The spreadsheet engine is loaded only when you open your first file.
Can I export a single sheet or the whole workbook?
Both. By default the export covers the selected sheet; tick All sheets to include every sheet in the workbook.
How do I turn a CSV into a real Excel file?
Open the CSV, then use the XLSX workbook export — this is offered when the file you loaded is a CSV — to save a proper .xlsx file.
What does the JSON export contain?
It converts the sheet's rows into structured JSON, which is handy for feeding spreadsheet data into code or other tools.
Tips
- Only the first 100 rows show in the preview, but exports include the whole sheet.
- Use the PDF export when you need a fixed, shareable snapshot of a sheet rather than editable data.
- Converting CSV to JSON or back to XLSX is a quick way to clean up data exported from another app.