Poster sizes

US posters are sold in inch sizes that do not belong to any paper series: 11 × 17, 18 × 24 and 24 × 36 in are the common ones, and movie one-sheets are 27 × 40 in. Europe uses the ISO A series directly — A2 (420 × 594 mm), A1 (594 × 841 mm), A0 (841 × 1189 mm) — and Japan uses JIS B1 (728 × 1030 mm) and B2 (515 × 728 mm) for station and street posters.

Korea is a trap: the "A2 poster" a Korean print shop sells is usually 423 × 597 mm, not ISO A2, and its "A1" is 597 × 849 mm. The sizes are cut from Korea's own parent sheets (636 × 939 mm and 788 × 1091 mm), so they land a few millimetres off the ISO figures. If the poster has to fit a standard ISO frame, check the shop's real trim size first.

Large posters are viewed from a distance, so safe margins are wider than on small print — 5 mm or more is sensible — and many shops accept lower resolution (around 150 dpi at full size) because nobody reads a poster from 30 cm away.