Skip to main content

International Envelope Series



Belonging to the ISO 216 standard, C8 is a unique paper size that holds its own significance in the world of print and design. This particular size, measuring 57 x 81 millimeters, is part of the C series under this globally recognized standard. The C series is specifically designed for envelopes and often used in conjunction with the A series.

The intriguing aspect about C8 lies in its dimensions. It's precisely calculated to accommodate an A8 sheet when folded into two equal parts. This meticulous design consideration ensures a seamless fit, making it an ideal choice for sending out invitations or small greeting cards.

C8 paper dimensions


View All International Envelope 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

Another fascinating fact about C8 and indeed all sizes within the ISO 216 standard is their aspect ratio. Maintaining a consistent ratio of 1:√2 across all sizes, they exhibit an impressive property - when cut or folded in half along their larger side, they retain their original aspect ratio. This unique feature provides immense flexibility in scaling content without distortion.

While not as commonly used as its counterparts like A4 or B5, C8 has found its niche use-cases due to its compact size and perfect compatibility with A8 documents. Whether you're crafting personalized invitations or designing compact product brochures, understanding and utilizing this distinctive paper size can add a professional touch to your print materials.

Other Formats in the International Envelope Series

Interesting facts about C8

1: C8 Paper Size

C8 paper is part of the ISO 216 standard, which defines the sizes of paper used globally. It measures 57 mm × 81 mm or approximately 2.24 inches × 3.19 inches.

2: Envelope Usage

C8 paper is commonly used for envelopes, particularly for small notes, gift cards, or business cards. Its compact size makes it ideal for enclosing small items.

3: Compact and Portable

The compact dimensions of C8 paper make it highly portable and convenient to carry in pockets or wallets. It is often used as a handy notepad for quick notes on the go.

4: European Origin

The ISO paper size system originated in Europe during the early twentieth century as a means to standardize paper sizes across countries and industries. C8 is one of the many sizes introduced by this system.

5: Part of A Series

C8 belongs to the A series of ISO paper sizes, which includes popular sizes like A0 (largest) to A10 (smallest). Each size in this series has a specific aspect ratio and can be easily scaled up or down while maintaining proportions.

6: Commonly Used in Japan

In Japan, C8-sized envelopes are often used for monetary gifts during special occasions like weddings or New Year celebrations. The small size symbolizes good luck and prosperity.

7: Historical Significance

Paper has been an essential medium for communication since ancient times. The development of standardized paper sizes like C8 has greatly facilitated printing, publishing, and international trade.

8: Paper Size Evolution

The ISO paper size system is based on the German DIN 476 standard introduced in 1922. It has since evolved to become the globally accepted standard for paper sizes, including C8.

9: Printing Efficiency

C8 paper size is often used by printers for test prints or proofing purposes due to its small dimensions. It allows for quick verification of layout and design elements before printing on larger sheets.

10: Unique Collectible Items

C8-sized papers, especially those with interesting designs or limited editions, have become collectible items among enthusiasts. They are sought after by collectors who appreciate the uniqueness and rarity of these small pieces of art.