What is the size of a2 paper?
A2 paper size is double of A3 paper size which is double of A4 paper size.
The size of A2 paper in cm is: 42 x 59.4
The size of A2 paper in inches is: 16.5 x 23.4

A2 is a very big paper size. We don’t use it in every day printers. It is used for posters in high quality (photo quality) and it’s expensive (25 sheets = 30-100$ depending the quality).It is very suitable for posters but you need to find a big printer.