This tool changes the paper size of every page in a PDF. Pick A4, US Letter, Legal, A3, A5 or type a custom width and height in millimetres or inches, choose portrait, landscape or Auto (each page keeps its own orientation), and add a margin if you want white space around the content. Each page's content is scaled to fit the new size, keeping its proportions, and centred. A before-and-after preview shows the result for any page.
The page is resized in place rather than printed again as an image, so text stays sharp and selectable, and links and form fields are moved and scaled with the content.
Limits: this changes the page size, not the file size (to make the file smaller, use a PDF compressor). When the old and new shapes differ, for example Letter to A4, the content is scaled down slightly and white space appears on two sides; nothing is cut off or stretched. Comments drawn as freehand ink may shift slightly on unusual files.