What paper size is larger than A1?

The paper size larger than A1 is A0. A0 measures 841 x 1189 millimeters (33.1 x 46.8 inches) and is the largest size in the A series. It is commonly used for large-format printing and technical drawings. Each subsequent size in the A series is half the area of the previous size when folded in half parallel to its shorter sides.