A3 Paper Size

What is A3 Paper Size?


A3 size is a common paper size used in non-American countries, it measures exactly 11.69″ x 16.54″ in inches, 297 x 420 in mm, or 29.7 x 42.0 in cm.

A3 is a size code in A paper series defined in accordance with ISO216, which specifies ISO standard paper sizes, one of the two most common paper standards in the world. Besides ISO A series, there are also ISO B paper series and ISO C envelope series.


In some countries in North America and non-American countries, such as the Philippines, people may not be familiar with expressions like A(x) Paper Size, because the American paper sizes, another one of the most common paper size standards is used in these regions.

World Regional Distribution of ISO Paper Sizes and American Paper Sizes
The areas in yellow are where A3 paper size is applied


It is usually applied to printing of larger drawings, charts or pictures with more information, such as maps; and also two-page laser printing for A4 paper, when one A4 sheet cannot cover.


This size is twice as large as A4 paper size, the most widely used in the world. The following figure shows the dimensions of a A3 sheet in inches and mm.

A3 Paper Size
A3 Paper Size

A3 Size Chart

A3 Dimensions in inches, mm, and cm

Size # in inches in mm in cm
A3 11.69″ x 16.54″ 297 x 420 29.7 x 42.0

A3 Dimensions in Pixels

A3 dimensions vary in pixels, depending on the PPI/DPI applied.

Size # 72 dpi/ppi
(screen resolution)
96 dpi/ppi
(screen resolution)
300 dpi/ppi
(print resolution)
A3 842 x 1191 px 1123 x 1587 px 3507 x 4962 px

* PPI (pixels per inch) = DPI (dots per inch) = Resolution

A Series Size Relations

If A3 size is evenly divided into two parts with the same length-width ratio, each part will become a standard A4 size. This is because it follows the overall rule of ISO216 paper size, and the ratio of length to width of each paper is √2:1. According to this ratio, starting from A0 to A1A2A3A4A5A6A7A8, A9, A10, etc., then each size is twice of the next size.

The following drawing shows the relationship between the sizes of the ISO A size.

A Paper Sizes Chart
A Paper Sizes Chart

A3 Size is NOT the Same as ANSI B 11×17 Paper size

In many articles explaining poster size, the author would equate A3 size with 11×17 paper size, which is not rigorous. A3 paper can indeed be alternative of 11×17 paper in some cases because of the similar dimensions of each other, but they are different by definition.


  • A3 Paper: 
    Used in non-North American countries, its size belongs to ISO A paper sizes;
  • 11×17 Paper:
    Specifically called ANSI B paper, or Tabloid / Ledger paper depending on its orientation, used in North America, Mexico, and Philippines, and its size belongs to US paper sizes.
A3 Size VS 11x17 Paper Size
A3 Size VS 11×17 Paper Size

A3 size in inches is: 11.69″x16.54″, close to 11″x17″, however absolutely different. Learn more of 11×17 paper size.

Main Facts of A3 Size

A3 Dimensions:
in inches: 11.69 x 16.54″
in mm: 297 x 420 mm
in cm: 29.7 x 42.0

A3 size in pixels:
in 72 ppi/dpi: 842 x 1191 px
in 96 ppi/dpi: 1123 x 1587 px
in 300 dpi/ppi: 1754 x 2480 px

Area: 1/8 square meter.

Country of use: Most countries except North America, Mexico, and the Philippines

Other name: DIN A3 Size

Usage: Mostly used to print larger drawings, charts or pictures with more information, such as maps; posters; also two-page laser printing for A4 paper, when one A4 paper cannot cover.

Advantages: Can be used to make complex drawings, and more information can be printed.

Disadvantages: Limited by common printing equipment for office use; inconvenient to make books or booklets, as it is not portable.

Ratio: It follows the ratio of ISO216 size standard, length to width: 1.414:1, or √2:1.

Approximate American size: ANSI B (Tabloid or Ledger), which measures 11″ x 17″ in inches, 279 x 432 in mm or 27.9 x 43.2 in cm.