B Series Paper Sizes

The dimensions of the B series paper sizes, as defined by ISO 216, are given in the table below in both millimetres and inches. The B Series paper size chart to the right is a visual explanation of how the B paper sizes relate to each other.

Table of Paper Sizes From B0 to B10

Size	Height x Width (mm)	Height x Width (in)
B0	1414 x 1000 mm	55.7 x 39.4 in
B1	1000 x 707 mm	39.4 x 27.8 in
B2	707 x 500 mm	27.8 x 19.7 in
B3	500 x 353 mm	19.7 x 13.9 in
B4	353 x 250 mm	13.9 x 9.8 in
B5	250 x 176 mm	9.8 x 6.9 in
B6	176 x 125 mm	6.9 x 4.9 in
B7	125 x 88 mm	4.9 x. 3.5 in
B8	88 x 62 mm	3.5 x 2.4 in
B9	62 x 44 mm	2.4 x 1.7 in
B10	44 x 31 mm	1.7 x 1.2 in

B Series Paper Size
ISO 216 specifies tolerances for the production of B series paper sizes in the same way as for A series paper sizes, the specific details of which are as follows:
Tolerances:

• ±1.5 mm (0.06 in) for dimensions up to 150 mm (5.9 in)
• ±2 mm (0.08 in) for lengths in the range 150 to 600 mm (5.9 to 23.6 in)
• ±3 mm (0.12 in) for any dimension above 600 mm (23.6 in)

B Series Paper Sizes Definition
The B series paper sizes are defined in ISO 216 in the following way.

The B series paper sizes were created in order to provide paper sizes that weren't covered by the A series, but also use an aspect ratio of 1:root2. B sizes are defined as size B(n) being the geometric mean of size A(n) and size A(n-1). The Geometric Means of 2 numbers being the square root of the product of the two numbers.

This system gives a useful property for enlarging and reducing documents in that the enlargement from A(n) to B(n) is the same as that from B(n) to A(n-1).

As with the A series paper the standard lengths and widths are rounded to the nearest millimetre.