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International Envelope Series



Belonging to the ISO 216 series, the C6/C5 paper size is a unique and versatile format. This particular size, measuring 114mm x 229mm, is part of the C series in the international standard. It's designed to accommodate B series paper sizes when folded, making it an ideal choice for envelopes.

The C6/C5 size holds a distinctive position in the ISO hierarchy. It's precisely half of a C5 sheet and twice that of a C7 sheet. This systematic scaling allows for seamless transitions between different sizes within the same series.

C6/C5 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 European origins, this paper size has gained global acceptance due to its practicality and versatility. From business correspondence to personal letters, it serves multiple purposes across various domains.

Moreover, it aligns with ANSI standards as well - specifically with Monarch and Commercial envelope sizes used predominantly in North America. This compatibility further enhances its universal appeal.

Whether you're aiming for professional communication or personal touchpoints, choosing the C6/C5 paper size can be an effective strategy. Its standardized dimensions ensure consistency while its adaptability makes it suitable for diverse applications.

Other Formats in the International Envelope Series

Interesting facts about C6/C5

1: C6/C5 Paper Size

C6/C5 paper is a unique size that combines the dimensions of two popular paper sizes, C6 and C5. It measures approximately 162 x 229 mm (6.38 x 9.02 inches).

2: Envelope Compatibility

C6/C5 paper is commonly used for envelopes as it perfectly fits an unfolded A4 sheet or an A5 sheet folded in half.

3: International Standard

The C series of paper sizes, including C6 and C5, is part of the international standard ISO 216, which was first introduced in the early 20th century.

4: Origin of ISO Paper Sizes

The ISO paper size system originated from a German standard called DIN (Deutsche Industrie Norm), which was introduced in the early 1920s.

5: Proportional Ratios

All ISO paper sizes maintain a consistent aspect ratio of √2 (approximately 1.414). This means that when you fold a larger size in half, you get two smaller sheets with the same proportions.

6: Common Uses

C6/C5 paper is often used for various purposes such as letters, invitations, greeting cards, and marketing materials like brochures or flyers.

7: European Preference

The use of C series papers is more prevalent in Europe compared to other regions where different sizing standards may be followed.

8: Alternative Names

In some countries, C6/C5 paper may be referred to by alternative names such as "A5/6" or "A4/3" due to its compatibility with those sizes.

9: Paper Weight Variations

C6/C5 paper is available in various weights, ranging from lightweight for everyday use to heavier cardstock for more durable applications.

10: Environmental Considerations

When choosing C6/C5 paper, you can opt for eco-friendly options made from recycled materials or certified sustainable sources, contributing to a greener printing industry.