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International Envelope Series



Belonging to the ISO 216 standard, C10 is a unique paper size that holds its own significance in the world of print and design. This particular size, measuring 28 x 40 millimeters, is part of the C series under ISO 216, which is internationally recognized for defining paper sizes.

The C series is specifically designed for envelopes and often used in conjunction with the A series. The dimensions of a C10 envelope are precisely calculated to accommodate an A10 sheet when folded in half. This meticulous design consideration ensures a perfect fit every time, enhancing both practicality and aesthetic appeal.

C10 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

Interestingly, despite its small size, the C10 plays an integral role in specific niches such as philately - the study of stamps and postal history. Stamp collectors worldwide appreciate this compact envelope size for storing valuable postage stamps safely.

Moreover, it's worth noting that while ANSI standards are prevalent in North America, they do not include an equivalent to the ISO's C10 size. This fact further underscores its unique position within global paper sizing standards.

Though seemingly insignificant due to its diminutive dimensions, the C10 paper size carries substantial weight within certain circles due to its precise fit with A10 sheets and niche applications like stamp collecting.

Other Formats in the International Envelope Series

Interesting facts about C10

1: C10 paper is not a standard paper size

C10 paper is not part of the ISO 216 standard for paper sizes. It is a non-standard size that falls outside the commonly used A, B, and C series.

2: C10 paper has unique dimensions

The dimensions of C10 paper are 917 mm x 1297 mm (36.1 in x 51.1 in). Its aspect ratio is approximately 1:1.42.

3: C10 paper is rarely used commercially

C10 paper is not commonly found in commercial printing or office supply stores. Its usage is limited to specific applications or custom requirements.

4: C10 paper can be used for large format printing

Due to its larger size, C10 paper can be suitable for large format printing projects such as posters, banners, or architectural plans.

5: The origin of the name "C" series

The "C" series of papers was introduced by the German Institute for Standardization (DIN) in the early twentieth century. The letter "C" stands for "circular," referring to the geometric progression of sizes within this series.

6: The relationship between A, B, and C series papers

The A and B series papers are derived from the geometric progression of sizes within the C series. For example, two sheets of A(n) size will equal one sheet of A(n+1) size, while two sheets of B(n) size will equal one sheet of B(n+1) size.

7: The purpose behind the C series

The C series was primarily designed to provide envelope sizes that would perfectly fit the corresponding A series paper sizes. For instance, an A4 sheet fits perfectly into a C4 envelope.

8: The largest standard size in the C series

C10 is the largest standard size within the C series. It is significantly larger than other commonly used sizes like C5 or C6.

9: Customization options for C10 paper

As it is not a widely available size, obtaining pre-cut or pre-packaged C10 paper may be challenging. However, some specialized printing companies can provide custom cutting services for this particular size.

10: Historical usage of non-standard paper sizes

In the past, non-standard paper sizes like C10 were more common due to variations in regional standards and specific industry requirements. However, with the widespread adoption of ISO 216 standard sizes, these non-standard sizes have become less prevalent.