ISO 'A' series paper size definition

A' size or 'A' series is a set of paper sizes established by the International Organization for Standardization (ISO).  Sizes range from 4A0 (the largest) to A10 (the smallest).

The physical size of the paper goes down as the number goes up, and each is simply half the size of the previous.  For example... two A4 sheets make up an A3 piece, and two A5 sheets make up an A4 sheet.

www.iso.org

ISO A and B/C series sizes (mm & inch values)

Format

A series

B series

C series

Size

mm × mm

in × in

mm × mm

in × in

mm × mm

in × in

0

841 × 1189

33.1 × 46.8

1000 × 1414

39.4 × 55.7

917 × 1297

36.1 × 51.1

1

594 × 841

23.4 × 33.1

707 × 1000

27.8 × 39.4

648 × 917

25.5 × 36.1

2

420 × 594

16.5 × 23.4

500 × 707

19.7 × 27.8

458 × 648

18.0 × 25.5

3

297 × 420

11.7 × 16.5

353 × 500

13.9 × 19.7

324 × 458

12.8 × 18.0

4

210 × 297

8.3 × 11.7

250 × 353

9.8 × 13.9

228 × 324

9.0 × 12.8

5

148 × 210

5.8 × 8.3

176 × 250

6.9 × 9.8

162 × 229

6.4 × 9.0

6

105 × 148

4.1 × 5.8

125 × 176

4.9 × 6.9

114 × 162

4.5 × 6.4

7

74 × 105

2.9 × 4.1

88 × 125

3.5 × 4.9

81 × 114.9

3.2 × 4.5

8

52 × 74

2.0 × 2.9

62 × 88

2.4 × 3.5

57 × 81

2.2 × 3.2

9

37 × 52

1.5 × 2.0

44 × 62

1.7 × 2.4

40 × 57

1.6 × 2.2

10

26 × 37

1.0 × 1.5

31 × 44

1.2 × 1.7

28 × 40

1.1 × 1.6