Paper Sizes Explained: A5, B5, Letter & Notebooks

Six notebooks drawn to one scale and labelled by paper size, from US Letter to 3.5 by 5.5 in — Six notebooks, six sizes, one scale (1 mm = 0.72 px).

Products compared

Product	Brand origin	Made in	Price range
Leuchtturm1917 Notebook Medium (A5), Hardcover, 251 numbered pages (dotted, ruled, squared or plain)Leuchtturm1917	Germany	Varies (Taiwan or Germany)^*	Price range: $$$$20–75 per notebook
Hobonichi Techo Original Book, A6, 2027 (English or Japanese; January or April start)Hobonichi	Japan	Not stated^*	Price range: $$$$20–75 per notebook
KOKUYO Campus Notebook, Semi-B5, 30 sheets (NO-3BN 6 mm rule; NO-3BTN 6 mm dotted; NO-3ATN 7 mm dotted)KOKUYO	Japan	Japan^*	Price range: $under $5 per notebook
TRAVELER'S notebook, Regular Size, leather cover starter kit (Brown, Blue, Olive and other colors)Traveler's Company	Japan	Thailand (cover); Japan (refill)^*	Price range: $$$$20–75 per notebook
Rocketbook Core Reusable Smart Notebook (Letter 8.5 × 11 in, 32 pages · Executive 6 × 8.8 in, 36 pages)Rocketbook	United States	Not stated^*	Price range: $$$$20–75 per notebook
Field Notes Original Kraft Memo Book, 3-Pack (graph, ruled, plain or mixed)Field Notes	United States	United States^*	Price range: $under $5 per notebook

Notes on these facts

Leuchtturm1917 Notebook Medium (A5), Hardcover, 251 numbered pages (dotted, ruled, squared or plain): Made by Leuchtturm Gruppe (Geesthacht, Germany). Made in Varies (Taiwan or Germany): Retailer data conflicts. Galaxus has listed Germany for a forest-green Medium dotted hard cover; Digitec has listed Germany, Taiwan and United Kingdom for a red-violet one; several eBay listings for Medium A5 notebooks have given Taiwan (all three now block automated reading). Leuchtturm1917's German and US product pages name no country for the standard notebook; its US 120G page says that edition's paper is made in Germany. Check the label on your copy. Source. Price: example listing. Released: Unsharpen dates the Leuchtturm1917 notebook brand to 2005; we found no separate date for the A5 Medium. The company itself dates to 1917.
Hobonichi Techo Original Book, A6, 2027 (English or Japanese; January or April start): Made by Hobonichi Co., Ltd. (Tokyo). Country of manufacture not stated: Hobonichi's Japanese store listing for the 2027 English Original gives size, weight, pages and paper but no country of manufacture (it names one only for a free charm, made in China), and we found no retailer spec sheet that states it for the Original Book. Hunter Paper Co. says its Original Avec book is made in Japan by Hobonichi, but that is a different product. Check the back of the book. Price: example listing. Released: Hobonichi's history page gives October 5, 2001 as the release date of the first edition, the 2002 Techo.
KOKUYO Campus Notebook, Semi-B5, 30 sheets (NO-3BN 6 mm rule; NO-3BTN 6 mm dotted; NO-3ATN 7 mm dotted): Made by KOKUYO Co., Ltd.. Made in Japan: KOKUYO's own global online store gives Country of Origin: Japan for the NO-3BN 3-pack and 10-pack and for the NO-3BTN and NO-3ATN dotted books. KOKUYO's Japanese catalog pages don't list origin; other Campus lines and sizes may differ. Source. Price: example listing. Released: KOKUYO's Japanese chronicle: the Campus brand began with spiral notebooks in 1965; this perfect-bound Campus Note followed in 1975, and the current design is the fifth generation, from October 2011.
TRAVELER'S notebook, Regular Size, leather cover starter kit (Brown, Blue, Olive and other colors): Made by Designphil Inc. (Tokyo). Made in Thailand (cover); Japan (refill): Traveler's Company says the leather cover is made in Chiang Mai, Thailand, and the notebook refill in Japan; its Japanese product page for the Brown Regular marks the cover MADE IN THAILAND. Retailer spec sheets (Pulp Addiction, Paper Whisper) give the same split. Source. Price: example listing. Released: Traveler's Company says the notebook launched in Japan in March 2006 with five refills, under the Midori brand.
Rocketbook Core Reusable Smart Notebook (Letter 8.5 × 11 in, 32 pages · Executive 6 × 8.8 in, 36 pages): Made by Rocketbook (Boston), a BIC company since December 2020. Country of manufacture not stated: Rocketbook's product page and FAQ don't state a country of manufacture. In October 2026 OnTimeSupplies' spec sheets gave China (CN) for both the Executive (RKBERCAFR) and Letter (RKBLRCAFR) Core, while UK distributor TBSG had listed the United States of America (its page no longer loads for us). Check the label on your pack. Source. Price: example listing. Released: First sold as the Everlast through Kickstarter pre-orders in December 2016, shipping from April 2017 (Pocketables); reviews call the Core the former Everlast (Top Ten Reviews).
Field Notes Original Kraft Memo Book, 3-Pack (graph, ruled, plain or mixed): Made by Field Notes Brand (Chicago); a joint venture of Draplin Design Co. and Coudal Partners. Made in United States: Field Notes' spec sheet, as reproduced in full by Pulp Addiction, says all Field Notes memo books are printed and manufactured in the U.S.A. and names the printer, Schneider Graphics, Inc., of Bensenville, Illinois. Jenni Bick also lists made in USA. Duluth Trading has said some components may be imported. Field Notes' own site blocked our requests, so we read the spec sheet through retailers. Source. Price: example listing. Released: Wikipedia dates the Field Notes launch to 2007; the spec-sheet copy says the first product was a 3-pack of kraft memo books with graph paper, with plain following shortly after, and Draplin's hand-made gift versions came earlier.
Price bands are typical US retail, checked October 2026.

Key takeaways

Every ISO A size has sides in the ratio 1:√2, so folding A4 (210 × 297 mm) in half gives A5 (148 × 210 mm), and A5 in half gives A6 (105 × 148 mm).
Japanese B5 under JIS P 0138 is 182 × 257 mm, while ISO B5 is 176 × 250 mm; KOKUYO's Campus notebook uses Semi-B5, 179 × 252 mm.
US Letter is 8.5 × 11 in (215.9 × 279.4 mm), about 6 mm wider and 18 mm shorter than A4; Half Letter is 5.5 × 8.5 in (139.7 × 215.9 mm).
TRAVELER'S notebook refills are 110 × 210 mm (Regular) and 89 × 124 mm (Passport); the Hobonichi Techo Original is A6, the Cousin A5 and the Weeks 95 × 186 mm in White Line covers.
Notebooks sold as A5 are often trimmed narrower: Leuchtturm1917 lists its Medium (A5) at 145 × 210 mm and Moleskine its Large at 13 × 21 cm.

How do A sizes work?

A sizes come from the international standard ISO 216: every sheet has sides in the ratio 1:√2, so cutting one in half gives the next size down with the same shape. A0 has an area of one square metre, A4 is 210 × 297 mm and A5, half of A4, is 148 × 210 mm.

The system began as the German DIN 476 standard in 1922 and became ISO 216 in 1975, per Wikipedia’s history of paper sizes. Today almost every country uses it except the United States and Canada.

Twelve paper sizes drawn to scale, from A4 and US Letter down to the TRAVELER'S Passport refill — Twelve sizes to one scale (1 mm = 0.9 px); cream sheets are notebook formats.

What are the common paper sizes in mm and inches?

These are the sizes stationery buyers meet most, with the standard that defines each.

Size	mm	inches	Standard	Typical use
A4	210 × 297	8.3 × 11.7	ISO 216	Printer paper outside the US, large notebooks
US Letter	215.9 × 279.4	8.5 × 11	ANSI/ASME Y14.1 (ANSI A)	US printer paper, spiral notebooks
B5 (JIS)	182 × 257	7.2 × 10.1	JIS P 0138	Japanese school notebooks
B5 (ISO)	176 × 250	6.9 × 9.8	ISO 216	Books, European notebooks
A5	148 × 210	5.8 × 8.3	ISO 216	Journals, bullet journals, planners
Half Letter	139.7 × 215.9	5.5 × 8.5	US (half of Letter)	US planners, sketchbooks
B6 (JIS)	128 × 182	5.0 × 7.2	JIS P 0138	Japanese diaries, notebooks
B6 (ISO)	125 × 176	4.9 × 6.9	ISO 216	Paperbacks
A6	105 × 148	4.1 × 5.8	ISO 216	Pocket notebooks, Hobonichi Original

Inch figures are our conversions, rounded to 0.1 in.

Why are there two B5 sizes?

Japan’s JIS P 0138 standard keeps the ISO A series but defines its own B series, with 1.5 times the area of the matching A size. That makes Japanese B5 182 × 257 mm, against 176 × 250 mm for ISO B5, and Japanese B6 128 × 182 mm against 125 × 176 mm.

Most Japanese notebooks follow the JIS figures. KOKUYO’s Campus notebook uses Semi-B5, 179 × 252 mm, trimmed slightly inside JIS B5, and Leuchtturm1917 sells a Composition (B5) at 178 × 254 mm. Our A5 vs B5 notebooks guide explains which size suits a carried journal and which suits class notes.

How do US Letter and Half Letter compare with A4 and A5?

US Letter is 8.5 × 11 in, about 6 mm wider and 18 mm shorter than A4; Half Letter, 5.5 × 8.5 in, is the US counterpart to A5. ANSI/ASME Y14.1 names Letter “ANSI A”, and Half Letter is also sold as Statement.

The difference matters for refills and covers. A Half Letter page is about 8 mm narrower and 6 mm taller than A5, so an A5 cover may hold it loosely or crop it. The Rocketbook Core comes in Letter, 8.5 × 11 in.

Which notebooks use which size?

A5 is the most common journal size, but many brands trim their “A5” or use their own formats.

Notebook	Sold as	Measured size	Nearest standard
Leuchtturm1917 Medium	Medium (A5)	145 × 210 mm	A5
Leuchtturm1917 Pocket	Pocket (A6)	90 × 150 mm	A6
Leuchtturm1917 Paperback	B6+	125 × 190 mm	B6
Moleskine Classic Large	Large	130 × 210 mm	A5 height
Midori MD Notebook A5	A5	148 × 210 mm	A5
Hobonichi Techo Original	A6	105 × 148 mm	A6
Hobonichi Techo Cousin	A5	148 × 210 mm	A5
Hobonichi Weeks	Weeks	95 × 186 mm (White Line)	None
KOKUYO Campus	Semi-B5	179 × 252 mm	JIS B5
Rocketbook Core	Letter	8.5 × 11 in	US Letter
Field Notes Original	Memo book	3.5 × 5.5 in (89 × 140 mm)	None

Leuchtturm1917 gives its sizes on its German product page and Moleskine on its Italian one; the other sizes come from our guides to each notebook. Our notebook sizes chart lists every size from nine notebook brands in mm, cm and inches.

What size is a TRAVELER’S notebook?

The Regular size takes 110 × 210 mm refills in a 120 × 220 mm cowhide cover, and the Passport size takes 89 × 124 mm refills. The Regular is as tall as A5 but only 110 mm wide, so A5 refills don’t fit; see our TRAVELER’S notebook Regular guide.

The Passport is close to A6 in width but shorter. Both sizes are their own formats rather than an ISO, JIS or US standard.

Which paper size should you choose?

Choose by where the notebook lives: A5 or B6 for a desk journal you also carry, A6 or Passport for a pocket, and B5, A4 or Letter for study and work notes.

A5 (148 × 210 mm): the default for journals and bullet journals, with the widest choice of covers and refills.
B6 (128 × 182 mm): a lighter bag notebook that still fits a page of writing.
A6 (105 × 148 mm) and Passport (89 × 124 mm): fit a jacket pocket; the Hobonichi Original fits a full day on one A6 page.
B5, A4 and Letter: room for lecture notes and printouts. In the US, Letter matches printers and binders; in Japan, B5 is the school standard.

Buying a cover or refill? Check the measured size in millimetres, not just the name, because brands trim the same nominal size differently.

Frequently asked questions

What size is A5 in inches?

A5 is 148 × 210 mm, which is about 5.8 × 8.3 inches. It is half an A4 sheet, and it is the most common size for journals and bullet journals.

Is A5 the same as Half Letter?

No, but they are close. Half Letter is 5.5 × 8.5 in (139.7 × 215.9 mm), about 8 mm narrower and 6 mm taller than A5, so covers and planner inserts for one don't always fit the other.

What is the difference between B5 and A5?

B5 is bigger. Japanese B5 (JIS P 0138) is 182 × 257 mm and ISO B5 is 176 × 250 mm, against 148 × 210 mm for A5. B5 sits between A5 and A4 and is a common size for Japanese school notebooks.

Why is Japanese B5 different from ISO B5?

Japan's JIS P 0138 standard defines its own B series with 1.5 times the area of the matching A size, instead of ISO's in-between sizes. So JIS B5 is 182 × 257 mm and ISO B5 is 176 × 250 mm.

Is A4 the same as US Letter?

No. A4 is 210 × 297 mm (8.3 × 11.7 in) and US Letter is 8.5 × 11 in (215.9 × 279.4 mm), so Letter is slightly wider and noticeably shorter.

Do A5 refills fit a TRAVELER'S notebook?

No. The Regular TRAVELER'S notebook is as tall as A5 but takes 110 mm wide refills, so a 148 mm wide A5 refill is too wide for its cover.

What size is a Hobonichi Techo?

The Original is A6 (105 × 148 mm), the Cousin is A5 (148 × 210 mm) and the Weeks is a slim 95 × 186 mm (94 × 188 mm in most covers other than White Line), per Hobonichi's 2027 editions.

What size is a Moleskine Large?

13 × 21 cm (5 × 8.25 in). It is the same height as A5 but 18 mm narrower, so A5 covers fit loosely.

Sources (10)

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