B3 and B2 paper sizes in cm: JIS vs ISO, plus B1, B0 and print pixels

JIS B3 is 36.4 × 51.5 cm (364 × 515 mm); JIS B2 is 51.5 × 72.8 cm (515 × 728 mm). ISO B3 is 35.3 × 50 cm, and ISO B2 is 50 × 70.7 cm.

A Japanese poster, a frame labelled B2 and a printer’s quotation may all lead you to this question. As with B4 and B5, first establish which B standard is intended.

B3 and B2: two standards

In Taiwan, B3 and B2 usually mean JIS, reflecting Japanese printing, stationery and frame specifications. The ISO dimensions may appear in international specifications or European equipment. The differences are about 1.1 × 1.5 cm for B3 and 1.5 × 2.1 cm for B2. Choosing the wrong standard can leave a border or crop the poster.

These are diagrams of the size relationship, not scale templates for cutting paper. Standard dimensions are listed in whole millimetres, so rounding can create small differences when halving: 707 mm on ISO B2 becomes 353.5 mm, whereas the listed ISO B3 side is 353 mm.

flowchart TB
    B2["ISO B2<br/>500 × 707 mm"] -->|"Halve the long side"| B3["Two ISO B3<br/>each 353 × 500 mm"]

flowchart TB
    B2["JIS B2<br/>515 × 728 mm"] -->|"Halve the long side"| B3["Two JIS B3<br/>each 364 × 515 mm"]

Two B3 sheets make one B2

Like A paper, each step in the B series halves or doubles the area. Its theoretical aspect ratio is 1:√2, so scaling preserves the shape.

B2 folds to B3, B3 to B4, and B4 to B5. Two JIS B4 sheets placed side by side correspond to one B3. These are standard size relationships, subject to whole-millimetre rounding.

• B1: Four B3 sheets
• B2: Two B3 sheets
• B3: Reference
• B4: Half of B3
• B5: A quarter of B3

Why JIS and ISO differ

The A series uses one set of dimensions, while the B series has two definitions. ISO B sizes sit at the geometric mean between adjacent A sizes: ISO B3 falls between A3 and A2. JIS B sizes have approximately 1.5 times the area of the same-numbered A size. Consequently, every JIS B size is slightly larger than its ISO counterpart. The JIS figures are the familiar ones for Taiwanese copiers, notebooks and frames.

Where B3 and B2 fit among A sizes

B3 is larger than A3 but smaller than A2; B2 is larger than A2 but smaller than A1. JIS B has about 1.5 times the area of the same-numbered A size. If A3 is too small and A2 too large, B3 provides the intermediate option.

Taiwanese printing sheets are different

Taiwanese printers also use divisions of a 54.6 × 78.7 cm half-sheet. These are not B sizes. The half-sheet is 54.6 × 78.7 cm, versus JIS B2 at 51.5 × 72.8 cm: about 3.1 cm wider and 5.9 cm longer. The quarter-sheet (4開) is 39.3 × 54.6 cm, versus JIS B3 at 36.4 × 51.5 cm: about 2.9 cm wider and 3.1 cm longer.

An order for B3 and one for a Taiwanese quarter-sheet produce different sheets. Give the dimensions in centimetres when having a Japanese poster printed in Taiwan.

Japanese posters and frames

• B0 and B1 are used for large posters in Japanese stations and passageways, including station advertisements supporting performers. B1 is also used for large exhibition graphics.
• B2 is a common size for Japanese shop posters and anime or idol merchandise posters. A Japanese “B2 ポスター” means 51.5 × 72.8 cm.
• B3 suits smaller posters, shop notices and displays. Japanese frames are sold with B3 and B2 size labels.
• In Taiwan, locally printed posters more often use A sizes or printing-sheet divisions; B3 and B2 often arise when framing merchandise from Japan.

Measure the actual poster and the frame’s internal opening before buying. A B2 label and the usable opening can differ by a few millimetres. Consider the display location and viewing distance as well as the size.

Pixels for B3 and B2 printing

Use the formula: millimetres ÷ 25.4 × DPI. The result depends on the standard as well as the resolution.

Posters viewed from one or two metres away are usually adequately served by 150 DPI. Text and photographic detail viewed close up may call for 300 DPI. A JIS B2 file at 300 DPI exceeds 50 million pixels and can be demanding for an ordinary computer; confirm that you need that resolution first.

Questions

How many centimetres is B3?

JIS B3 is 36.4 × 51.5 cm (364 × 515 mm); ISO B3 is 35.3 × 50 cm. In Taiwan, B3 generally refers to JIS. Japanese poster frames use the JIS size.

How many centimetres is B2?

JIS B2 is 51.5 × 72.8 cm (515 × 728 mm); ISO B2 is 50 × 70.7 cm. One B2 corresponds to two B3 sheets in the same standard, allowing for rounding. B2 is common for Japanese shop and merchandise posters.

Is B3 larger than A3, and B2 larger than A2?

Yes. JIS B3 (36.4 × 51.5 cm) lies between A3 (29.7 × 42 cm) and A2 (42 × 59.4 cm). JIS B2 (51.5 × 72.8 cm) lies between A2 and A1 (59.4 × 84.1 cm). JIS B has about 1.5 times the area of the same-numbered A size.

Is B3 the same as a Taiwanese quarter-sheet?

No. The Taiwanese 4開 size is 39.3 × 54.6 cm, about 2.9 cm wider and 3.1 cm longer than JIS B3. The 54.6 × 78.7 cm half-sheet is also larger than JIS B2. State both the sheet system and the dimensions.

How many pixels are needed for a B2 poster?

JIS B2 is 6083 × 8598 px at 300 DPI or 3041 × 4299 px at 150 DPI. Posters viewed at a distance usually need only 150 DPI; close-up text or photographic detail may need 300 DPI.