XLSX ↔ CSV / JSON
Convert Excel/ODS spreadsheets to CSV or JSON and back to XLSX — in your browser, nothing uploaded.
published
- [FREE]
- [NO_SIGNUP]
- [NO_UPLOAD]
XLSX ↔ CSV / JSON converts spreadsheets both directions in your browser — no upload, no signup.
Private by default
Files are parsed and written locally with SheetJS; nothing is sent to a server — the key difference from typical “convert Excel online” sites. Reads .xlsx/.xls/.ods/.csv (multi-sheet) → CSV or JSON, and pasted CSV/JSON → .xlsx.
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Frequently asked questions
Is my spreadsheet uploaded?
No. The file is parsed in your browser with SheetJS and never leaves your device — unlike most "convert Excel online" sites that upload your file to a server. Verify in DevTools → Network.
What formats does it read and write?
Reads .xlsx, .xls, .ods, and .csv (multi-sheet workbooks supported — pick a sheet). Exports the selected sheet to CSV or JSON, and converts pasted CSV or a JSON array back to a downloadable .xlsx.
How are multiple sheets handled?
All sheet names are listed; choose one to preview and export. Convert each sheet separately.
Does it preserve formulas/formatting?
Conversion targets data, not presentation: cell values are exported (computed values for formulas where available). Styling, charts, and merged-cell layout are not carried into CSV/JSON.