Smallest Poster - 11 x 17 Inches. Also called Ledger, Tabloid or ANSI B size. This is the smallest standard poster size, they are mostly used for flyers, street lights, bulletin boards, and generally putting up on businesses without taking up too much room and offending. These also work great with a minimalist approach to text. Big letters big message. Size in Millimetres is 279 x 432mm.