A4 vs US Letter: what’s the difference?

The two sheets, measured

A4 is 210 × 297 mm (8.27 × 11.69 in) — taller and slightly narrower. US Letter is 215.9 × 279.4 mm (8.5 × 11 in) — wider and shorter. A4 belongs to the ISO 216 family, which has an elegant property: every size has the same √2 proportions, so folding an A4 in half gives an A5, and two A4s side by side make an A3, all with identical shape. Letter has no such family — its companions (Legal, Tabloid) are historical accidents of American office practice.

Who uses which

US Letter is standard in the United States, Canada, Mexico and parts of Central and South America. Virtually everywhere else — Europe, Asia, Africa, Oceania — uses A4. This split is why every generator on Printable Park offers both as a one-click option rather than assuming: a template drawn only for Letter wastes a centimeter of every A4 sheet and vice versa.

Printing one on the other

Printing an A4 document on Letter paper (or the reverse) works, with one of two compromises. Scale to fit: the page shrinks ~3–6% — fine for text and calendars, wrong for anything measured (see printing at actual size). Print at 100% and crop: the content stays exact but the overhanging edge clips — safe with our templates only if margins are generous. The better answer is simply to download the right version: switch the Paper size option on any template page and the PDF is rebuilt for your sheet, no scaling involved.

Which should you pick?

Use whatever your printer tray holds — matching the physical paper beats every other consideration. The layouts here adapt: grids fill the available area with exact spacing either way, calendars stretch their boxes slightly wider on Letter and slightly taller on A4. If you share files internationally (a classroom pack, an office form), export both versions and label them; the thirty seconds saves every recipient the scaling trap.