A4 vs Letter vs Legal: resizing a PDF for the printer you actually have

A4 and US Letter are close enough in size that most people never notice the difference — until a document built for one gets printed on the other, and margins shift, content overflows onto a stray second page, or a print dialog's "fit to page" setting stretches everything just slightly out of proportion.

Why this happens

A4 is 210 × 297mm; US Letter is 8.5 × 11in (215.9 × 279.4mm) — narrower and taller versus wider and shorter, not just a different total area. A PDF's pages have their exact size baked in; a printer or PDF viewer set to "fit to page" is making a real-time guess about how to reconcile that with a different physical sheet, and guesses vary between printers and software.

Resizing properly instead of guessing at print time

Resize PDF Pages rescales every page to a real target size — A4, Letter, Legal, or A3 — ahead of time, so the file itself matches the paper rather than relying on the printer to reconcile a mismatch. Scaling is uniform (never stretched non-proportionally) and centered, so a size difference shows up as a bit of extra margin on two sides rather than as distortion.