Rename the file to .zip and look inside and you will usually find QuickLook/Preview.pdf, which is the whole document rendered by Apple. Taking that out is not a conversion at all, it is an extraction, which is why the result is exact rather than approximate. When the preview is missing, no tool can help, and the honest answer is to ask the sender for a PDF.
What is actually in a .pages file
It is not a document in the way a .docx is. It is a zip of an Apple package, and since iWork '13 the document body is stored as IWA: Apple's own protocol buffers, framed with Snappy compression, with an internal schema that is undocumented and changes between versions. Nothing outside Apple's software reads it reliably, and tools that claim to are guessing.
Alongside that body sits something far more useful. When a document is saved with previews enabled, which is the default, Pages writes a full PDF render of the finished document into the package so that Finder, Quick Look, Mail and iOS can show it without launching the app.
Index/*.iwa
The real document, in Apple's private binary format. Effectively unreadable elsewhere.
QuickLook/Preview.pdf
The whole document as a PDF, rendered by Apple with the right fonts. This is the prize.
Data/
Images and media placed in the document, in their original form.
Metadata/
Which version of Pages wrote the file, and the identifiers it uses for syncing.
Why this beats converting
Every other route has to rebuild the document. It reads whatever structure it can recover, guesses at the fonts (which are usually Apple's and not installed on your machine), re-flows the text, and hands you something that resembles the original. Tables shift, line breaks move, and a carefully placed image ends up a page later.
Extraction has none of those failure modes because there is no layout decision to make. The PDF was produced by Pages itself, on the author's machine, with the author's fonts. What you download is byte for byte what Apple wrote. This tool does not even re-save it through a PDF library, because re-saving is a chance to change something and there is nothing to gain by taking it.
Parse and rebuild
What most converters attempt. Fonts substituted, spacing drifts, tables break, and complex layouts come back wrong in ways that are hard to spot until someone points at page four.
Extract what Apple rendered
Exact fonts, exact spacing, exact pagination, because it is the same PDF you would get by printing from Pages on the author's Mac. Nothing is inferred.
When the preview is not there
Two cases. The first is a document saved with Include preview in document switched off, which some people turn off to keep file sizes down. The second is a very old iWork '09 file, which uses a different structure again.
In both cases the honest answer is that nothing can be done with the file alone, and any site that promises otherwise is either guessing at the layout or quietly failing. The fix lives with whoever has Pages: File then Export To then PDF, ten seconds of work, and the result is better than any conversion would have been anyway. This tool tells you that plainly rather than producing something broken.
A .key presentation and a .numbers spreadsheet use the same package layout and carry the same preview, so both convert here. For Numbers the preview reflects the print layout, which is worth checking against what you expected, because a very wide sheet gets split across pages.
Questions people actually ask
What people ask when a .pages file lands on a Windows machine.
01Can I edit the result?
It is an ordinary PDF, so you can annotate, sign, fill fields and reorder pages with the tools on this site. You cannot get back to an editable word processor document, because the PDF records the finished layout rather than the structure that produced it.
02Is the text selectable?
Yes. Apple's preview is real text with embedded fonts, not a picture of the page, so search, copy and select all work.
03The page count is lower than the document I was told about.
The preview reflects the document as it was last saved. If the sender edited after that without saving, or saved from a different device, the preview can lag. When the count looks wrong, ask for an exported PDF.
04What about .pages files from iCloud?
They are the same package and work the same way. If you can open the document in iCloud Pages in a browser, exporting to PDF from there is also a good route and needs no Mac either.
05Does the file get uploaded?
No. The zip is opened in your browser with JavaScript and the PDF inside is handed to you directly. Nothing is transmitted.