A3 size: dimensions and most common uses
The dimensions of size A3 are as follows: 297 x 420 mm or 29.7 x 42 cm. Compared to other formats, A3 is: double A4, four times A5, half A2 and a quarter of A1. Like the other most common formats, A3 is regulated by international paper size standard ISO 216, based on German standard DIN 476.
An A3 sheet has the following dimensions in inches/pixels:
Remember that with pixels, the dimensions depend on the resolution. The higher the resolution, the higher the number of pixels.