“Resize the PDF” can mean changing only the page box or scaling the content too
This tool offers Fit, Stretch, and Page only. Fit preserves the aspect ratio, Stretch scales width and height independently, and Page only changes the page size without moving the existing content.
Those choices can produce very different results even when the target is the same A4 size.
Fit preserves proportions but can leave empty margins
Fit scales the original page uniformly and centers it on the new page. If the source aspect ratio differs from the destination paper, some margin remains.
Stretch can remove that margin, but may distort text, logos, or other content.
Page only changes the outside box without repositioning content
In Page only mode, the existing content keeps its scale and position while the page dimensions change. If the new page is smaller, parts of the original content can end up outside the visible area.
Open the saved PDF and check for clipping before using it.
Forms and annotations need an extra visual check
Scaling and translating the page content does not guarantee that every complex form field or annotation will follow in exactly the same way. The tool warns about that after conversion.
If you only need to inspect the current dimensions first, use PDF page size checker.