International Paper sizes
International Paper Sizes are a standardised system of related sheets sizes, based on a series of three different sizes called A, B or C - all of the same proportions.
Definition of weight, or "substance", of paper is expressed in constant terms as "grammes per square metre" (or gsm); if a sheet of AO paper weighs 90 grammes it is then described as "90 gsm", regardless of the actual size of the sheets.

The A Series
| size | millimetres | size | millimetres |
|
4A0
2A0
AO
A1
A2
A3
|
1682x2378
1189x1682
841x1189
594x841
420x594
297x420
|
A4
A5
A6
A7
A8
A9
|
210x297
148x210
105x148
74x105
52x74
37x52
|
The B Series
The basic B size, called B0, measures 1000x1414mm
| size | millimetres | size | millimetres |
|
B0
B1
B2
B3
B4
|
1000x1414
707x1000
500x707
353x500
250x353
|
B5
B6
B7
B8
B9
|
176x250
125x177
88x125
62x88
44x62
|
The C Series
| size | millimetres | size | millimetres |
|
C0
C1
C2
C3
|
917x297
648x917
458x648
324x458
|
C4
C5
C6
C7
|
229x324
162x229
114x162
81x114
|
International Envelope Sizes
| size | millimetres | size | millimetres |
|
C3
B4
C4
B5
C5
B6/C4
|
324x458
250x353
229x324
176x250
162x229
324x176
|
B6
C6
DL
C7/6
C7
|
125x176
114x162
110x220
81x162
81x114 |
|