International standard paper sizes used worldwide. The ISO system includes A series for general use, B series for posters, and C series for envelopes.
ISO 216
The ISO A series is the most widely used paper size standard worldwide, based on a constant aspect ratio of √2.
Size
mm
inch
4A0
1682 × 2378
66.2 × 93.6
2A0
1189 × 1682
46.8 × 66.2
A0
841 × 1189
33.1 × 46.8
A1
594 × 841
23.4 × 33.1
A2
420 × 594
16.5 × 23.4
A3
297 × 420
11.7 × 16.5
A4
210 × 297
8.3 × 11.7
A5
148 × 210
5.8 × 8.3
A6
105 × 148
4.1 × 5.8
A7
74 × 105
2.9 × 4.1
A8
52 × 74
2 × 2.9
A9
37 × 52
1.5 × 2
A10
26 × 37
1 × 1.5
ISO 216
The ISO B series is an intermediate size between consecutive A series sizes, providing additional options for paper dimensions.
Size
mm
inch
B0
1000 × 1414
39.4 × 55.7
B1
707 × 1000
27.8 × 39.4
B2
500 × 707
19.7 × 27.8
B3
353 × 500
13.9 × 19.7
B4
250 × 353
9.8 × 13.9
B5
176 × 250
6.9 × 9.8
B6
125 × 176
4.9 × 6.9
B7
88 × 125
3.5 × 4.9
B8
62 × 88
2.4 × 3.5
B9
44 × 62
1.7 × 2.4
B10
31 × 44
1.2 × 1.7
ISO 269
The ISO C series is primarily used for envelopes designed to fit A series paper sizes. Each C size is the geometric mean between the corresponding A and B sizes.