A3 Paper Size, Dimensions and Format (A series)

A3 in millimeters

297 x 420




Aspect ratio 1:1.41
Area (A) 124,740 mm²
Perimeter (P) 1,434 mm
Diagonal (d) 514.40 mm


The A3 format measures 297 x 420 mm or 11.7 x 16.5 inches. An A3 paper fromat has an aspect ratio of 1:1.41. The Area of the A3 paper size is 124,740 mm² or 193.05 in² with a perimeter of 1,434 mm or 56.40 in. An A3 format has a diagonal length of 514.40 mm or 20.23 in. The A3 size belongs to the A series. In the A series there are a total of 19 paper sizes.

Frequently Asked Questions:

The size of an A3 paper is 297 x 420 mm

The size of an A3 paper in inches is 11.7 x 16.5 in

The half size of an A3 paper is 148.5 x 210 mm or 5.85 x 8.25 in

The aspect ratio of an A3 is 1:1.41

The area of an A3 paper is 124,740 mm or 193.05 in

The perimeter of an A3 paper is 1,434 mm or 56.40 in

The diagonal measurement of A3 paper is 514.40 mm or 20.23 in

Other A Paper Sizes

There are a total of 19 A Paper Sizes.