Skip to main content
XLSX is Microsoft Excel’s default workbook format since Excel 2007. It is a ZIP package that follows the Office Open XML standard (SpreadsheetML): each sheet is an XML part, and each cell can hold a value, a formula and that formula’s last calculated result. Styles, defined names and charts live in their own parts.

​
Why it matters when generating documents with AI

  • A useful sheet stores formulas, not just numbers: change one input and the rest recalculates.
  • Numbers or dates stored as text don’t sum or sort correctly, even though they look the same.
  • Errors such as #REF! or #DIV/0! and broken references only show up when the workbook is calculated.
  • A language model can write plausible but made-up figures; formulas make it visible where each result comes from.

​
With Doconda

With format: "xlsx", Doconda creates an Excel workbook with real formulas (not pasted numbers), with assumptions in their own cells and no calculation errors, plus its PDF (Create). When editing, changes are made with formulas too. When reviewing, it detects formula errors, numbers stored as text, hidden data and inconsistent formulas, and gives the sheet and cells.