ISO Paper sizes

In the ISO paper size system, the height-to-width ratio of all pages is the square root of two (1.4142 : 1). In other words, the width and the height of a page relate to each other like the side and the diagonal of a square. This aspect ratio is especially convenient for a paper size. If you put two such pages next to each other, or equivalently cut one parallel to its shorter side into two equal pieces, then the resulting page will have again the same width/height ratio.

The ISO paper sizes are based on the metric system. The square-root-of-two ratio does not permit both the height and width of the pages to be nicely rounded metric lengths. Therefore, the area of the pages has been defined to have round metric values. As paper is usually specified in g/m≤, this simplifies calculation of the mass of a document if the format and number of pages are known.

ISO Sizes A series

ISO Code	Size in millimeters	Size in inches	Size in Points
4A0	1682 mm x 2378 mm	66.22 in x 93.62 in	4768 pt x 6741 pt
2A0	1189 mm x 1682 mm	46.81 in x 66.22 in	3370 pt x 4768 pt
A0	841 mm x 1189 mm	33 in x 46.81 in	2384 pt x 3370 pt
A1	594 mm x 841 mm	23.39 in x 33 in	1684 pt x 2384 pt
A2	420 mm x 594 mm	16.54 in x 23.36 in	1191 pt x 1684 pt
A3	297 mm x 420 mm	11.69 in x 16.54 in	842 pt x 1191 pt
A4	210 mm 297 mm	8.27 in x 11.69 in	595 pt x 842 pt
A5	148 mm x 210 mm	5.83 in x 8.27 in	420 pt x 595 pt
A6	105 mm x 148 mm	4.13 in x 5.83 in	298 pt x 420 pt
A7	74 mm x 105 mm	2.91 in x 4.13 in	210 pt x 298 pt
A8	52 mm x 74 mm	2.05 in x 2.91 in	147 pt x 210 pt
A9	37 mm x 52 mm	1.46 in x 2.05 in	105 pt x 147 pt
A10	26 mm x 37 mm	1.02 in x 1.46 in	74 pt x 105 pt

The B series formats are geometric means between the A series format with the same number and the A series format with one lower number. For example, B1 is a geometric mean between A1 and A0. The sides of B0 are 1 m to v2 m.

ISO Sizes B series

ISO Code	Size in millimeters	Size in inches	Size in Points
B0	1000 mm x 1414 mm	33.37 in x 55.67 in	2836 pt x 4008 pt
B1	707 mm x 1000 mm	27.84 in x 39.37 in	2004 pt x 2835 pt
B2	500 mm x 707 mm	19.69 in x 27.84 in	1417 pt x 2004 pt
B3	353 mm x 500 mm	13.9 in x 19.69 in	1001 pt x 1417 pt
B4	250 mm x 352 mm	9.84 in x 13.9 in	709 pt x 1001 pt
B5	176 mm x 250 mm	6.93 in x 9.84 in	499 pt x 709 pt
B6	125 mm x 176 mm	4.92 in x 6.93 in	354 pt x 499 pt
B7	88 mm x 125 mm	3.47 in x 4.92 in	249 pt x 354 pt
B8	62 mm x 88 mm	2.44 in x 3.47 in	176 pt x 249 pt
B9	44 mm x 62 mm	1.73 in x 2.44 in	125 pt x 176 pt
B10	31 mm x 44 mm	1.22 in x 1.73 in	88 pt x 125 pt

ISO size variations

The following sizes are all variations on paper sizes in the ISO series. Since these are european standards, the size in inches is aproxiamte.

Name	Size in millimeters	Size in inches
A2 extra	445 mm x 619 mm	17.51 in x 24.3 in
A3 extra	322 mm x 445 mm	12.67 in x 17.51 in
A3 Super	305 mm x 508 mm	12 in x 20 in
Super A3	305 mm x 487 mm	12 in x 19.17 in
A4 extra	235 mm x 322 mm	9.25 in x 12.67 in
A4 Super	229 mm x 322 mm	9.25 in x 12.67 in
Super A4	227 mm x 356 mm	8.93 in x 14.01 in
A4 Long	210 mm x 348 mm	8.26 in x 13.7 in
A5 extra	173 mm x 235 mm	8.26 in x 9.25 in
SO B5 extra	202 mm x 276 mm	7.95 in x 10.86 in

The current ISO 216 standard was introduced in 1975 and is a direct follow up to the german DIN 476 standard from 1922. The Netherlands have used the DIN/ISO standard since 1925, Belgium since 1924, England (UK) since 1959 and France since 1967. ISO 216 is also called EN 20216 in Europe.

For the ISO C series please refer to our over view of ISO Envelope sizes.

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