A-format

German paper-format. The edges are in relation 1:SQRT(2). The most common format is A4, which edges are 210 mm x 297 mm long. Smaller formats (increasing numbers) take a half of the next bigger format, bigger formats (decreasing numbers) are double sized.
The biggest supported size is A0, which has 841 mm x 1189 mm. The smallest is A5 with 148 mm x 210 mm.

1 mm = 0.03937 inch