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Paper Sizes Explained

Paper Sizes Explained

July 27, 2021 - Posted by Ryan to Guides, Paper, Beginners' Guides, Stationery 101

Paper Sizes Explained

A4, B5, A5—these are some of the most commonly used paper sizes in the world, but to North Americans they may sound more like bingo calls than paper sizes. In the US, Canada, and Mexico, the standard paper size is Letter size: 8.5" × 11". Outside of North America, however, Letter size is rarely used.1 Instead, other countries use a system of paper sizes that may seem confusing at first but is actually quite simple and logical once you understand the methodology behind it.

Read on or watch the video below to learn more about how international paper sizes work, how different sizes compare to Letter size, and which paper sizes work best for different applications.

Understanding International Paper Sizes

Most countries outside of North America use paper that fall into one of two sizes: the A sizes and the B sizes. There are also C sizes, but it is mainly used for creating envelopes manufactured to fit A size papers, so we won't discuss it here. A sizes are more commonly used than B sizes, so let's begin with them.

A Sizes
A Sizes
A sizes
A sizes of paper were originally introduced in Germany during the 1920s and quickly spread throughout Europe. By the 1970s it became widely used throughout the world and was codified by the International Organization for Standardization (ISO).

A sizes start with the largest size, A0, which is 84.1 cm × 118.9 cm, or about 33.1" × 46.8". Each smaller size is obtained by taking the next largest size and cutting it in half, creating a size with the same proportions and half the surface area.

A size aspect ratio
Cutting an item with an aspect ratio of 1:√2 yields two items with the same aspect ratio and half the surface area of the original.
In most cases, cutting a piece of paper in half would result in two pieces with completely different proportions than the original piece. In this case, however, it works due to the interesting mathematical phenomenon that when a sheet of paper with an aspect ratio (the ratio of its width to its length) of 1:√2 is cut it in half, the resulting two sheets of paper will have the same aspect ratio of 1:√2.2

Within the A sizes, A4 size is the closest to North American Letter size and is the standard paper size in countries that use A sizes. At approximately 8.3" × 11.7" (21 cm × 29.7 cm), it is slightly longer and narrower than Letter size.

B Sizes
B Sizes
B sizes
B sizes of paper sizes are based on the same principles as the A sizes, with an aspect ratio of 1:√2 and each size having half the area of the next largest size. The difference is that B sizes are in between the A sizes, offering improved granularity. For example, B5 size offers a choice halfway between A4 and A5.

Unfortunately, B sizes get a bit more complicated. Unlike A sizes, which are the same everywhere, the exact dimensions of B sizes are defined differently in Japan than they are in the rest of the world.

A4, B5, A5 comparison
B sizes are about half a size larger than A sizes, so B5 is about halfway between A4 and A5 in size.
The Japanese Industrial Standards Committee (JIS) defines B sizes as slightly larger than the ISO B sizes. Specifically, JIS B sizes are 6% larger in area and about 3% larger in width and length than ISO B sizes. Because of this, B size paper from Japanese brands is often (but not always) slightly larger than B size paper from non-Japanese brands. One exception to this trend is with B5 size. Many Japanese brands that otherwise use JIS sizes for B size paper use a size for B5 similar to ISO B5, often (but not always) calling it "Semi B5" size.

If all of that is too complicated to remember, just note that B sizes can vary slightly from one product line to another, so be sure to check the specific product dimensions for any B size paper or notebook if it needs to be exactly the right size.

Common Paper Sizes

Below, we have listed the most commonly used paper sizes for loose leaf paper, notebooks, and notepads from largest to smallest. For B sizes, we list the Japanese sizes since they are much more commonly used among the products we carry. ISO B sizes are listed separately in a drop-down table further down. As explained above, A sizes are the same in Japan and internationally.

Size
(Large to Small)
Width Length Area Comparison to Letter Size
B4 (JIS) 10.1 in
25.7 cm
14.3 in
36.4 cm
145.0 in²
935.5 cm²
A4 8.3 in
21.0 cm
11.7 in
29.7 cm
96.7 in²
623.7 cm²
Letter 8.5 in
21.6 cm
11.0 in
27.9 cm
93.4 in²
602.6 cm²
B5 (JIS) 7.2 in
18.2 cm
10.1 in
25.7 cm
72.5 in²
467.7 cm²
Semi B5 (JIS) 7.0 in
17.7 cm
9.8 in
25.0 cm
68.6 in²
442.5 cm²
A5 5.8 in
14.8 cm
8.3 in
21.0 cm
48.2 in²
310.8 cm²
B6 (JIS) 5.0 in
12.8 cm
7.2 in
18.2 cm
36.1 in²
233.0 cm²
A6 4.1 in
10.5 cm
5.8 in
14.8 cm
24.1 in²
155.4 cm²
Pocket* 3.5 in
8.9 cm
5.5 in
14.0 cm
19.2 in²
124.6 cm²
B7 (JIS) 3.6 in
9.1 cm
5.0 in
12.8 cm
18.1 in²
116.5 cm²
A7 2.9 in
7.4 cm
4.1 in
10.5 cm
12.0 in²
77.7 cm²

*Pocket size is not standardized, but it is a commonly used size that is typically around 3.5" × 5.5".

Choosing a Paper Size

There are a few considerations to keep in mind when choosing a paper size. Larger paper sizes offer more space for writing and drawing, but they also take up more space on your desk, in your bag, or on your shelf. What size is right for you will depend on how and where you intend to use it. Here are some recommended paper sizes and products we think are best for a variety of applications.

School Notes

Recommended Sizes: A4, Letter, B5 / Semi B5

Students need plenty of space for taking notes, and since they often are carrying a backpack with them anyway, carrying a larger notebook or binder shouldn't be a problem. Assignments that need to be turned in will most likely need to be done on standard Letter size paper (or A4 paper for students outside of North America).

Maruman Mnemosyne Special Memo Notebook - A4

Maruman Mnemosyne notebooks feature high-quality paper and sleek, durable covers that will protect your notes from getting creased or crumpled in your backpack. A wide range of additional sizes and paper styles are also available.

Kokuyo Campus Notebook - Semi B5

With one of these slim and colorful notebooks for each class, you can easily keep your notes organized. You'll also know which notebooks to carry for the classes you have on any one day. Plus, the dotted line rule is great for creating diagrams, graphs, and other figures in your notes.

Kokuyo Campus Adapt Slim Binder - A4

This slim binder lets you easily change or reorganize your notes on the fly. Use it with pre-punched filler paper or make your own with a hole punch.

Office Notes

Recommended Sizes: A4, Letter, B5 / Semi B5, A5, B6, A6

The perfect paper size for office note-taking will depend on your desk space and how much writing you do. A copious note-taker with plenty of space will want a large notebook or notepad holder, while a simple notepad is perfect someone who just needs to jot down an occasional list or reminder.

Maruman Mnemosyne Notepad Holder - A4

Perfect for those with lots of notes and documents to keep track of, this holder includes an A4 notepad as well as five separate pockets for holding A4 or Letter sized papers. The holder is made from durable plastic and has an elastic band closure to keep its contents secure.

Kyokuto F.O.B. COOP W Ring Notebook - Semi B5

With its sleek, modern style, this notebook is at home in any office environment. Its convenient dot grid paper style makes it easy to write or draw on while being less conspicuous than a typical line or grid pattern.

Rhodia Ice Pad No. 13 - Graph - A6

This compact notepad is just right for jotting down quick notes and lists. It features a sleek white cover and subtle gray grid pattern.

Journal

Recommended Sizes: A5, B6, A6

The perfect journal is large enough to write out all your thoughts without feeling cramped, yet small enough to fit unobtrusively in a drawer or on a desk or nightstand. A medium-sized notebook in the A6 to A5 range is just right for this.

Rhodia Webnotebook - A5

Featuring the classic design of a hardcover notebook with an elastic closure and back cover pocket for storing notes and memorabilia, this notebook is a perfect receptacle for your thoughts and inspirations. Filled with smooth, high-quality 90 gsm paper, it is a particularly good choice for fountain pen users.

Exacompta Club Leatherette Journal - B6

These refillable, leatherette journals are available in a variety of fun and classic colors, letting you choose the one the best captures your personality. Each page of the journal insert features a perforated tear-off corner so that you can easily flip to the next unused page.

Midori MD Notebook - Standard - A6

These slim notebooks feature Midori Diary (MD) paper, which is well-loved for its ability to provide a pleasant experience for any writing instrument, especially fountain pens. It also includes label stickers, so you can index your journals and keep track of when you start and finish them.

Pocket Notebook

Recommended Sizes: Pocket, B7, A7

For taking notes on the go, a portable notebook should be small enough to carry easily in a pocket or bag. Pocket notebooks are just small enough to fit into a typical back pants pocket, while the smaller B7 and A7 sizes will fit more easily into a shirt, jacket, or front pants pocket.

TRAVELER'S COMPANY TRAVELER'S notebook - Passport Size

This durable leather notebook is actually a cover that can hold up to three staple-bound pocket notebooks at once! You can keep a planner, a notebook, and a sketchbook all together in one convenient cover and buy refills as necessary. The surface of the leather will gain a distinctive patina with use, reflecting the unique way that you have used and carried it.

Field Notes Memo Book - Pocket Size

A cult classic, these high-quality, made-in-the-USA memo books feature rugged staple binding and are available in a wide range of standard and seasonal editions.

Maruman M.Memo Mini Notepad - A7

These compact, colorful notepads feature firm yet flexible cardstock covers that will protect the notepad while easily conforming to the contours of your pocket. Lines on the front cover allow for easy labeling and indexing.

Sketchbook

Recommended Sizes: Any

A sketchbook can be as big or small as you want it to be. Sketch epic landscapes or intricate multi-panel drawings on an oversized B4 pad, quick thumbnails in a mini A7 notebook, or anything in between!

Maruman New Soho Series Sketchbook - B5

This sketch pad features lightly textured, heavyweight paper that is suitable for use with a wide range of wet and dry media. Its glue binding is sturdy but allows pages to be pulled out cleanly if desired. B4 and B6 versions are also available.

Stillman & Birn Premium Sketchbook - A5

These high-quality sketchbooks feature protective hard covers and a variety of paper types to choose from, each optimized for specific applications. For general sketching with pens and dry media, we recommend the Alpha Series Sketchbook.

Maruman Pocket Croquis Sketchbook - A6

These fun pocket sketchbooks are available in three different paper weights: 52.3 g. for pencils and other dry media, 60 g for inks and markers, and 96.4 g for light washes and watercolors.

Comics and Illustrations

Recommended Sizes: B4, A4, Letter

Illustrators and comic artists need plenty of space for creating detailed drawings. Professional Japanese manga artists use B4 paper for their work, but A4 or Letter size paper also provide a good amount of drawing space.

Deleter Comic Paper - B4

This professional-grade, loose leaf manga paper is available plain or with scale markings to help organize layouts. It is well-suited for use with ink, markers, and screen tones.

Strathmore 400 Series Mixed Media Pad - Black - 9" x 12"

This Strathmore pad (which is also available in white) features acid-free paper that combines the characteristics of both watercolor and drawing paper, making it the best choice for artists that use wet and dry media. The cardstock cover can be folded back when the pad is in use and the glue binding allows sheets to be removed easily.

Stillman & Birn Nova Sketchbook 7.5” x 7.5”- Mixed Trio

Artists that are only familiar with white sketchbooks, this softcover Stillman & Birn mixed trio sketchbook may intrigue you! Best suited for light washes and dry media, it is filled with 46 sheets of archival quality paper—16 black, 15 beige, and 15 gray—which is perfect if you are looking to experiment with light and dark media.

Conclusion

We hope that this article has helped some of you to understand international paper sizes. They can seem complicated at first, but like the metric system they are actually pretty straightforward once you understand how they work. Do you have a favorite paper size for journaling, sketching, or note-taking? Let us know in the comments section below!

Recommended Uses for Different Paper Sizes
Size
(Large To Small)
Width Length Area Recommended Use
B4 (JIS) 10.1 in
25.7 cm
14.3 in
36.4 cm
145.0 in²
935.5 cm²
Sketchbook, Comics and Illustrations
A4 8.3 in
21.0 cm
11.7 in
29.7 cm
96.7 in²
623.7 cm²
School Notes, Office Notes, Sketchbook, Comics and Illustrations
Letter 8.5 in
21.6 cm
11.0 in
27.9 cm
93.4 in²
602.6 cm²
School Notes, Office Notes, Sketchbook, Comics and Illustrations
B5 (JIS) 7.2 in
18.2 cm
10.1 in
25.7 cm
72.5 in²
467.7 cm²
School Notes, Office Notes, Sketchbook
Semi B5 (JIS) 7.0 in
17.7 cm
9.8 in
25.0 cm
68.6 in²
442.5 cm²
School Notes, Office Notes, Sketchbook
A5 5.8 in
14.8 cm
8.3 in
21.0 cm
48.2 in²
310.8 cm²
Office Notes, Journal, Sketchbook
B6 (JIS) 5.0 in
12.8 cm
7.2 in
18.2 cm
36.1 in²
233.0 cm²
Office Notes, Journal, Sketchbook
A6 4.1 in
10.5 cm
5.8 in
14.8 cm
24.1 in²
155.4 cm²
Office Notes, Journal, Sketchbook
Pocket* 3.5 in
8.9 cm
5.5 in
14.0 cm
19.2 in²
124.6 cm²
Pocket Notebook, Sketchbook
B7 (JIS) 3.6 in
9.1 cm
5.0 in
12.8 cm
18.1 in²
116.5 cm²
Pocket Notebook, Sketchbook
A7 2.9 in
7.4 cm
4.1 in
10.5 cm
12.0 in²
77.7 cm²
Pocket Notebook, Sketchbook

Footnotes:

1) Outside of North America, Letter size is sometimes referred to as American Quarto.
2) To demonstrate this phenomenon mathematically, suppose there is a sheet of paper with a long side of length a and a short side of length b, such that a/b = √2. Cutting this sheet of paper in half results in a new sheet with a long side of length b, a short side of length a/2, and an aspect ratio of b/(a/2). It then follows that: b/(a/2) = 2/(a/b) = 2/√2 = √2