Yes. Upload your .xlsx file and edit cell values, formulas, and formatting directly in the browser grid, then download a faithful .xlsx that opens cleanly in Excel.

Editing a value marks the workbook to recalculate on open, so Excel recomputes formulas itself the next time you open the file rather than relying on a stale cached result.

No. Editing runs entirely in your browser, so your spreadsheet data never leaves your device.