Dimensions of the A series paper sizes 4A0, 2A0, A0, A1, A2, A3, A4, A5, A6, A7, A8, A9 and A10 in both inches and mm, cm measurements can be obtained. An A3 piece of paper measures 297 × 420 mm or 11. The A3 size print measures 29. A3 measures 420 x 297 mm or 16. Popular paper sizes and printing formats: A0, A1, A2, A3, A4, A5, A6, A7, A8.