What is A3 Paper Size?
Definition
A3 size is 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.
A3 is a mid-range size in the A series paper standard, falling between A2 and A4. It’s a versatile format commonly used for larger documents, graphics, and designs that need more space than a standard letter-size sheet but are still manageable in everyday settings. A3 paper is often used in both professional and educational environments for presentations, drawings, and posters that require attention but aren’t as large as those printed on A2 or A1.
Dimensions
A3 size measures exactly 11.69″ x 16.54″ in inches, 297 x 420 in mm, or 29.7 x 42.0 in cm.
This size is half the dimensions of A2 when folded or cut, following the same halving principle of the A-series. A3 offers a perfect balance between space for content and practicality, being larger than the common A4 size but still compact enough to be used in most office printers and other equipment.
Layout
The following figure shows the dimensions of a A3 sheet in inches and mm. It is 29.7 x 42.0 in cm.
Regions
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.
Usage
A3 paper is highly versatile and is used in a wide variety of applications:
- Posters and Signage: A3 is frequently used for smaller posters, signs, and promotional material that need more space than standard-sized sheets like A4 but are still compact enough for easy handling and distribution.
- Design and Drafting: Graphic designers and architects often use it for mock-ups, blueprints, and drafts that require larger dimensions for better visualization without becoming cumbersome.
- Educational Materials: In classrooms or educational settings, it is used for larger worksheets, visual aids, or posters that need to be displayed in a larger format for visibility.
- Calendars and Planners: The paper is popular for wall calendars, planners, or other time-management tools that need larger spaces for daily or weekly entries.
- Photographic Prints: Photographers may use A3 for printing high-quality photos or artwork, as it’s large enough to showcase details but small enough to fit into standard frames for display.
- Brochures and Flyers: Marketing materials like brochures or informational handouts are often printed in A3, allowing for ample space for images and text without being overly large for storage or distribution.
A3 Size in inches
11.69 x 16.54 in
A3 Size in cm
29.7 x 42.0 cm
A3 Size in mm
297 x 420 mm
A3 Dimensions Table
| 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 Paper Size
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 A1, A2, A3, A4, A5, A6, A7, A8, 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.
A3 Size Alternatives in US
In the United States, there is no direct equivalent to A3 paper size. However, the closest equivalent is Tabloid size, which measures 11 x 17 inches. While both A3 and Tabloid are similar in dimension, Tabloid is slightly smaller than A3 (11.69 x 16.54 in). The U.S. Arch B size (12 x 18 inches) can also serve as a comparable option, although it is slightly larger than A3.
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.
Again,
-
A3 Paper: 11.69″ x 16.54″
Used in non-North American countries, its size belongs to ISO A paper sizes; -
11×17 Paper: 11″x17″
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.
Learn more of 11×17 paper size.
Main Facts
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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
- 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.
Arch B size, has dimensions of 12 x 18 in inches, 305 x 457 in mm, or 30.5 x 45.7 in cm.