The International Standard ISO 216 is a paper size standard that has been adopted by majority of the countries of the world. It is a metric-based system with a consistent ratio (1:1.4142) so that each size can be divided evenly into smaller half sheets. The benefit is that printed materials can easily be reproduced in different sizes without having to crop or change the layout of the item being printed. This optimizes the printer's costs by allowing them to use the the entire parent sheet and prevents excess paper from being wasted.

There are 3 commonly used parent sizes which include:

• A series – These sizes are the most commonly used for business documents and everyday use.

• B Series – These sizes are often used for posters, books, envelopes, and passports.

• C Series – These sizes are used for constructing envelopes as they are slightly larger than the A series so that a C4 envelope with fit an A4 piece of paper for example.

The ISO 216 standard has been adopted by the United Nations and the following countries:

There are also other standards or variances known as extensions in a few countries that are not listed here.

Click on an item number to get more information about its size and style. Size fits card and envelope.
Format	Metric	Inches	No Flap	Biodegradable No Flap	Flap Seal	Biodegradable Flap Seal	Protective Closure	Hanging
A0	841 x 1189	33.1" x 46.8"	-	-	B4735*	-	-	-
A1	594 x 841	23.4" x 33.1"	-	-	BA1	-	BA1PC	-
A2	420 x 594	16.5" x 23.4"	-	-	BA2	-	BA2PC	-
A3	297 x 420	11.7" x 16.5"	-	-	BA3	-	BA3PC	-
A4	210 x 297	8.3" x 11.7"	-	-	BA4	-	BA4PC	HBA4
A5	148 x 210	5.8" x 8.3"	-	-	BA5S	-	BA5SPC	-
A6	105 x 148	4.1" x 5.8"	-	-	BA6S	-	BA6SPC	-
A7	74 x 105	2.9" x 4.1"	B34CNF	-	B34	-	-	HB34
A8	52 x 74	2" x 2.9"	-	-	B23	-	-	HB23
A9	37 x 52	1.5" x 2"	-	-	-	-	-	-
A10	26 x 37	1" x 1.5"	-	-	-	-	-	-
B0	1000 x 1414	39.4" x 55.7"	-	-	B6040**	-	-	-
B1	707 x 1000	27.8" x 39.4"	-	-	B4432**	-	-	-
B2	500 x 707	19.7" x 27.8"	-	-	B2028	-	-	-
B3	353 x 500	13.9" x 19.7"	-	-	-	-	-	-
B4	250 x 353	9.8" x 13.9"	-	-	-	-	-	-
B5	176 x 250	6.9" x 9.8"	-	-	B711*	-	-	-
B6	125 x 176	4.9" x 6.9"	B75NF	GR75NF	B75S	-	B75SPC	HB75
B7	88 x 125	3.5" x 4.9"	-	-	B35	-	-	-
B8	62 x 88	2.4" x 3.5"	B23CNF	-	B2XL	-	-	HB23
B9	44 x 62	1.7" x 2.4"	-	-	-	-	-	-
B10	31 x 44	1.2" x 1.7"	-	-	-	-	-	-
C0	917 x 1297	36.1" x 51.1"	-	-	B6040**	-	-	-
C1	648 x 917	25.5" x 36.1"	-	-	B36*	-	-	-
C2	458 x 648	18" x 25.5"	-	-	-	-	-	-
C3	324 x 458	12.8" x 18"	-	-	-	-	-	-
C4	229 x 324	9" x 12.8"	-	-	B913	-	-	HB913
C5	162 x 229	6.4" x 9"	-	-	B610*	-	-	HB610*
C6	114 x 162	4.5" x 6.4"	-	-	B56M	-	-	HB56
C7	81 x 114	3.2" x 4.5"	-	-	B3X6*	-	-	-
C8	57 x 81	2.2" x 3.2"	B2NF	-	B2	-	B2PC	HB2
C9	40 x 57	1.6" x 2.2"	-	-	B1X2XL*	-	-	-
C10	28 x 40	1.1" x 1.6"	B1X2NF	-	-	-	-	-