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C Series



Belonging to the ISO 216 standard, C11 is a unique paper size that holds its own significance in the world of print and design. This particular size, measuring 324mm by 458mm, is part of the C series under this globally recognized standard. The ISO 216 standard has been adopted by all countries except Canada and the United States, making C11 a widely used paper size across various continents.

The C series is specifically designed for envelopes. The dimensions of C11 make it an ideal choice for enclosing B11 items or A11 folded once. This compatibility with other sizes within the ISO standards ensures seamless correspondence and packaging processes.

C11 paper dimensions


View All C Series

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

Interestingly, like all sizes in the ISO 216 standard, C11 adheres to an aspect ratio of √2:1. This unique ratio allows for easy scaling between sizes without distortion or loss of content - a feature that sets it apart from ANSI series used predominantly in North America.

Moreover, this specific aspect ratio also means that when two same-sized pieces are placed side by side along their longer edge, they form another paper size up in the series. In case of C11 sheets, placing two together would create a larger sheet equivalent to a C10.

Whether you're involved in international correspondence or intricate design projects requiring precise scaling capabilities - understanding and utilizing the distinctive properties of paper size like C11 can be instrumental to your success.

Other Formats in the C Series

Interesting facts about C11

1: C11 Paper Size

C11 paper is a part of the ISO 216 standard series, which defines the sizes of paper used globally. It measures 162 mm × 229 mm or approximately 6.38 inches × 9.02 inches.

2: Uncommonly Used

C11 paper size is not commonly used in everyday printing or stationery. It falls within the category of less frequently utilized paper sizes.

3: Envelope Compatibility

C11 paper can be used to create envelopes that fit A10-sized documents perfectly when folded in half.

4: Historical Origin

The ISO paper size system, including C11, originated from a German standard called DIN (Deutsches Institut für Normung) introduced in the early twentieth century.

5: Proportional Ratios

The ISO paper sizes, including C11, follow a consistent ratio of √2 (approximately 1.414). This means that when you fold a sheet in half along its longer side, you get two smaller sheets with the same proportions as the original.

6: International Adoption

The ISO paper size system has been widely adopted worldwide and is used by many countries as their national standard for printing and office use.

7: Series Continuity

The C series of ISO papers ranges from C0 (largest) to C10 (smallest), with each subsequent size being half the area of its predecessor while maintaining the same aspect ratio.

8: Common Uses for Other Sizes

In contrast to C11, other sizes in the C series, such as C4 and C5, are commonly used for envelopes and packaging materials.

9: Printing Industry Standards

The ISO paper size system is widely adopted in the printing industry due to its standardized dimensions, making it easier for printers to handle various paper sizes efficiently.

10: Paper Weight Variations

C11 paper can be found in different weights or thicknesses, allowing it to be used for a variety of purposes such as letterheads, brochures, or lightweight cards.