Excel's modern spreadsheet format — and, on iOS 26, one of the few things Filemorph can build directly out of a PDF's tables.
XLSX is Microsoft Excel's spreadsheet format, introduced alongside DOCX in Office 2007 and built the same way — an XML-based structure packed inside a ZIP archive rather than the older, more fragile binary .xls format. Unlike a CSV file, which stores only raw data, an XLSX file preserves formulas, multiple sheets, cell formatting, charts, and everything else that makes a spreadsheet a working tool rather than just a data dump, which is why real spreadsheet work happens in XLSX and not CSV despite CSV's wider compatibility. That richer structure is also what makes XLSX harder to produce from scratch on a phone: Filemorph can build one from a CSV file or a JSON array reliably, since both are just rows of data, but the more demanding job — pulling structured tables directly out of a PDF bank statement or report and turning them into a working spreadsheet — needs iOS 26 and Filemorph Pro, reflecting how much more computation that extraction actually requires.
iPhone, iPad, and Mac open XLSX in Numbers and Excel for iOS. Windows, Google Sheets, and virtually every modern spreadsheet program open it as the default format, though older software still using the .xls format may need a compatibility step.
A CSV export or a PDF's tables carry the data but none of a spreadsheet's structure, formulas, or multiple sheets. Converting to XLSX on-device turns raw exported data, or text extracted from a PDF, into a spreadsheet that is actually ready to work in.
Filemorph can convert XLSX to CSV on-device — a plain-text export that any other spreadsheet program or script can read without needing Excel specifically.
Filemorph converts .xlsx files entirely on-device on iPhone, iPad and Mac — no upload, no account, and it works in Airplane Mode.
Relevant operations in Filemorph:
CSV stores only raw rows and columns of text. XLSX preserves formulas, multiple sheets, cell formatting, and charts — the full working structure of a spreadsheet — which is why real spreadsheet work happens in XLSX while CSV stays the universal export format.
Yes, on iOS 26 with Filemorph Pro. Filemorph can extract tables from a PDF — a bank statement or report, for instance — directly into an XLSX spreadsheet, which takes noticeably more processing than a CSV-to-Excel conversion.
Yes. Filemorph converts XLSX files entirely on-device, so a spreadsheet with financial or personal data is never uploaded to a server, and the conversion works the same in Airplane Mode.