B Paper Sizes
B paper sizes are the ISO 216 series that fills the gaps between the A sizes. B5 is a common book and notebook size; B1 and B2 are standard poster sizes.
B0 measures 1000 millimetres wide and 1414 millimetres tall.
The B Paper Sizes to Scale
Dimensions of All B Paper Sizes
The B Paper Sizes run from B0 at 1000 × 1414 mm to B10 at 31 × 44 mm. Each size, with its closest US equivalent and typical use:
| Size | mm | cm | inches | Nearest US size | Common use |
|---|---|---|---|---|---|
| B0 | 1000 × 1414 | 100.0 × 141.4 | 39.37 × 55.67 | None | Billboards, large trade-show posters |
| B1 | 707 × 1000 | 70.7 × 100.0 | 27.83 × 39.37 | None | Standard large posters |
| B2 | 500 × 707 | 50.0 × 70.7 | 19.69 × 27.83 | None | Mid-size posters, window bills |
| B3 | 353 × 500 | 35.3 × 50.0 | 13.9 × 19.69 | None | Small posters, notices, wall charts |
| B4 | 250 × 353 | 25.0 × 35.3 | 9.84 × 13.9 | None | Large-format books, folded newspapers, envelopes |
| B5 | 176 × 250 | 17.6 × 25.0 | 6.93 × 9.84 | None | Academic books, textbooks, notebooks |
| B6 | 125 × 176 | 12.5 × 17.6 | 4.92 × 6.93 | None | Pocket books, passports open, diaries |
| B7 | 88 × 125 | 8.8 × 12.5 | 3.46 × 4.92 | None | Passports, pocket diaries, ID cards |
| B8 | 62 × 88 | 6.2 × 8.8 | 2.44 × 3.46 | None | Playing cards, labels, tickets |
| B9 | 44 × 62 | 4.4 × 6.2 | 1.73 × 2.44 | None | Small labels, stamps, tags |
| B10 | 31 × 44 | 3.1 × 4.4 | 1.22 × 1.73 | None | Stamps, micro-labels |
Dimensions are portrait (short edge first), rounded to the nearest millimetre exactly as ISO 216 defines them. Centimetre, inch and pixel values are derived by formula, not separate standards.
Where the B Paper Sizes Sit Between the A Sizes
The A series doubles in area at each step, which is a wide jump. The B series fills the middle. B(n) is the geometric mean of A(n) and A(n minus one), so B1 sits between A0 and A1, B5 between A4 and A5, and so on down the ladder. Print shops keep B1 and B2 for posters that need more presence than A1 without going to A0. Publishers use B5 and B6 for books when A5 pages feel cramped. A B4 envelope holds an unfolded A4 sheet with room to spare.
How the Japanese B Paper Sizes Differ from ISO B
There are two B5s. ISO B5 is 176 × 250 mm. Japanese JIS B5 is 182 × 257 mm, because the JIS B series is defined as 1.5 times the area of the matching A size rather than the geometric mean the ISO version uses. Both keep the 1 : √2 shape; only the scale differs. The gap matters for notebooks and manga volumes bought from Japan, and for setting a document that has to print correctly in both markets. The same 6 to 7 mm difference runs through B4, B6 and the rest of the JIS series.
Frequently Asked Questions
What are the ISO B paper sizes?
B0 to B10, defined by ISO 216. B0 is 1000 × 1414 mm and each size halves from there. Each B size sits between two A sizes of the same and previous number.
What is B5 paper used for?
Books, textbooks and notebooks. B5 sits between A5 and A4, giving more writing width than A5 while staying easy to carry.
Is JIS B5 the same as ISO B5?
No. ISO B5 is 176 × 250 mm; Japanese JIS B5 is 182 × 257 mm. The JIS B series is scaled to 1.5 times the matching A size.
What size is B2 paper?
500 × 707 mm, or 19.7 × 27.8 in. B2 is a common mid-size poster and showcard, larger than A2.
Do B paper sizes fold in half like A sizes?
Yes. The B series keeps the 1 : √2 proportion, so folding a B sheet across its long edge gives two of the next B size down with nothing trimmed.
✓ Member dimensions per ISO 216:2007. Centimetre, inch and pixel values derived by formula. Last verified . Editorial Process →