Japanese Paper & Book Size Comparison Cheat Sheet

Japanese stationery is trendy overseas, but we need to be aware that some items follow Japan’s own standards and be careful when buying them. Here is a table of commonly used Japanese paper size. And I will also explain the characteristics and use of each paper.

Japanese Paper Size Comparison

Millimeters (width × length)Inches (width × length)
A4210 × 297 mm8.3 × 11.7 in
B5182 × 257 mm7.2 × 10.1 in
A5148 × 210 mm5.8 × 8.3 in
Shirokuban <四六判>128 × 188 mm5.0 × 7.4 in
B6128 × 182 mm5.0 × 7.2 in
Shinsyo <新書>105 × 182 mm4.1 × 7.2 in
A6105 × 148 mm4.1 × 5.8 in

Many Japanese products are made based on Japan’s own standards “JIS (Japanese Industrial Standards)”, and therefore have different specifications from the international standards “ISO”.

JIS A size is exactly the same as ISO A size, so there is no problem. However, JIS B size is slightly larger than ISO B size, so please be careful. I recommend that you always check the size in the product description when you buy a B5 or B6 size Japanese notebook.

ISO B5: 176 x 250 mm
JIS B5: 182 x 257 mm

ISO B6: 125 × 176 mm
JIS B6: 128 × 182 mm

Japanese paper size
Image source:

Features of Each Paper Size in Japan

A4 (210 × 297 mm)

A4 size is commonly used in business occasions, even in Japan. Not many students use this size of paper to study as B5 is mainly popular among school students. (I remember I got surprised in the UK that people were using A4 size notebooks as they seemed to me too big at the first time.)

B5 (182 × 257 mm)

As mentioned, this is the most common size for Japanese students. It is probably because of the limited space available on the desks in Japanese schools.

A5 (148 × 210 mm)

The A5 size is popular for business use as we can open it in a limited space but still has enough writing space. People also use ring binders of this size.

Shirokuban <四六判> (128 × 188 mm)

This size is usually only used for books. Many hardcover books in Japan are also available in this size. 

B6 (128 × 182 mm)

If you find A5 a little difficult to carry around, you can use a slightly smaller b6 size. Many hardcover books in Japan are also available in this size.

Shinsyo <新書> (105 × 182 mm)

Shinsyo is a combination of B6 width and A6 length. It is a standard size for Japanese books, along with A5 and A6, but it’s a very rare size for notebooks. (Midori, a popular Japanese stationery brand, produces notebooks in this size.)

A6 (105 × 148 mm)

A6, also known as Bunko size in Japan, is the smallest in the typical notebook size. It can fit in the breast pocket of a jacket.

There are much smaller sizes like B7 and A7 suitable for memo pads, but we don’t find many as they are too small.

A wide range of Japanese stationery is available on Amazon Japan these days. But, please take note of the available sizes when you purchase.


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