The common letter-sized paper used in Europe and in most locations outside of North America. At 8.3 x 11.7" (210x297mm), A4 paper is slightly narrower and a little longer than "A" size 8.5 x 11 ...

A standard sheet of A4 paper, as typically defined by the International Organization for Standardization (ISO), measures just 8.27 inches wide and 11.69 inches long.