Paper size standards govern the size of sheets of paper used as writing paper, stationery, cards, and for some printed documents.
Paper sizes A0 to A8, life-size installation "The invasion of the square roots" at the CosmoCaixa Barcelona science museum
ISO 216 is an international standard for paper sizes, used around the world except in North America and parts of Latin America. The standard defines the "A", "B" and "C" series of paper sizes, which includes the A4, the most commonly available paper size worldwide. Two supplementary standards, ISO 217 and ISO 269, define related paper sizes; the ISO 269 "C" series is commonly listed alongside the A and B sizes.
Visualization with paper sizes in formats A0 to A8, exhibited at the science museum CosmoCaixa Barcelona
An A4 paper sheet folded into two A5 size pages