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US Series

Large Post

Large Post

Belonging to the ISO A series, Large Post is a paper size that stands out due to its unique dimensions. This format, measuring 419 x 533 mm or 16.5 x 21 inches, offers ample space for various applications, from architectural drawings to large-scale marketing materials.

As part of the ISO A series, Large Post adheres to an aspect ratio of √2:1. This ratio ensures that when the paper is folded in half along its shortest side, the resulting format retains the same aspect ratio. It's a feature that sets ISO standards apart and contributes significantly to their global adoption.

Large Post paper dimensions


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2A046.81 x 66.221189 x 1682119 x 1683370 x 4768
A120.51 x 0.7113 x 181 x 237 x 51
4A066.22 x 93.621682 x 2378168 x 2384768 x 6741
A110.71 x 1.0218 x 262 x 351 x 74
A101.02 x 1.4626 x 373 x 474 x 105
A3+12.95 x 19.02329 x 48333 x 48933 x 1369
A1+23.98 x 35.98609 x 91461 x 911726 x 2591
A0+35.98 x 50.87914 x 129291 x 1292591 x 3662
A64.13 x 5.83105 x 14811 x 15298 x 420
A55.83 x 8.27148 x 21015 x 21420 x 595
A48.27 x 11.69210 x 29721 x 30595 x 842
A311.69 x 16.54297 x 42030 x 42842 x 1191
A91.46 x 2.0537 x 524 x 5105 x 147
A216.54 x 23.39420 x 59442 x 591191 x 1684
A82.05 x 2.9152 x 745 x 7147 x 210
A123.39 x 33.11594 x 84159 x 841684 x 2384
A72.91 x 4.1374 x 1057 x 11210 x 298
A033.11 x 46.81841 x 118984 x 1192384 x 3370

The Large Post size also finds relevance in ANSI standards - specifically within the B series. Known as ANSI B or Tabloid in North America, it shares similar dimensions with Large Post but differs slightly at 279 x 432 mm or 11 x 17 inches.

Interestingly enough, despite these slight differences in measurements between ISO and ANSI standards, both formats are often used interchangeably in professional settings due to their close proximity in size.

Whether you're drafting detailed blueprints or designing eye-catching posters, the Large Post paper size provides a versatile canvas for your creative and professional needs.

Other Formats in the US Series

Interesting facts about Large Post

1: Large Post paper is part of the ISO 216 standard

Large Post paper, also known as A3 paper, is a standardized size that falls under the ISO 216 international paper size standard. It measures 297mm x 420mm or approximately 11.7 inches x 16.5 inches.

2: Large Post paper was originally developed in Germany

The ISO 216 standard, including the Large Post size, was first introduced in Germany in the early 20th century. It aimed to create a consistent and efficient system for paper sizes.

3: Large Post paper is twice the size of A4

A3 or Large Post paper is exactly twice the size of A4 paper. When an A3 sheet is folded in half, it becomes an A4 sheet.

4: Large Post paper is commonly used for architectural drawings and posters

The larger surface area of A3/Large Post makes it ideal for architectural drawings, technical diagrams, and posters that require more space to showcase detailed information or artwork.

5: Large Post printers are designed specifically for this size

To accommodate printing on A3/Large Post-sized sheets, specialized printers are available that can handle this larger format. These printers often have adjustable trays and feed mechanisms to support printing on various sizes of media.

6: The aspect ratio of Large Post paper is √2

The aspect ratio (width-to-height ratio) of all ISO standard papers, including Large Post/A3, is √2 (approximately equal to 1.414). This means that when you divide the longer side by the shorter side, you get the same value.

7: Large Post paper is widely used in art and design industries

Artists, graphic designers, and photographers often prefer working on A3/Large Post-sized sheets due to the ample space it provides for sketching, illustrating, or presenting their work.

8: Large Post paper can be easily scaled from other ISO sizes

One of the advantages of ISO standard paper sizes is their scalability. For example, an A2 sheet can be divided into two equal A3 sheets, while two A3 sheets combined create an A2 sheet.

9: Large Post paper is not commonly used for everyday office printing

In most office environments, A4 paper remains the standard choice for everyday printing needs. Large Post/A3 paper is typically reserved for specific purposes that require a larger format.

10: The ISO 216 standard has its roots in ancient Egyptian papyrus rolls

The concept of standardized paper sizes can be traced back to ancient Egypt where papyrus rolls were used. These rolls had fixed widths but could vary in length. The ISO 216 standard draws inspiration from this historical practice by maintaining consistent aspect ratios across different sizes.