Most notebooks get abandoned for a dull reason: the size was wrong. A pad that won't fit a coat pocket, or one so narrow the lines crowd your handwriting, ends up in a drawer alongside three of its siblings. Online listings rarely help, since "medium" and "large" mean whatever the brand wants them to mean. Here is what the letters and numbers actually tell you, and which details are worth checking before you pay.
Why the letter matters more than the brand
A-series paper is a simple halving system. A5 is half of A4, A6 is half of A5, and the proportions stay identical at every step, which is why a sheet of A5 folded in half makes a tidy A6 booklet. Learn four numbers and you can judge almost any listing in seconds:
- A4: 210 × 297 mm
- A5: 148 × 210 mm
- A6: 105 × 148 mm
- A7: 74 × 105 mm
B-series sizes follow the same logic but sit between the A sizes, so B5 falls between A5 and A4. That makes it a genuine middle ground and, for plenty of writers, the most comfortable size for long sessions.
The sizes you will actually see in UK shops
A4: the desk notebook
Big, flat and generous. A4 suits lecture notes, first drafts, project planning and mind maps, where you want a full page of space and room to draw arrows between ideas. It is a poor travelling companion: too tall for most coat pockets, and heavy once you pass a couple of hundred pages.
A5: the default
If you own one notebook, it is probably this. A5 slips into a messenger bag, a rucksack front pocket or a large coat pocket, and it fits most journal covers and refill systems. With 7 mm ruling you get roughly 25 to 30 lines a page, which is enough for a daily entry, a meeting's worth of notes or a page of study summary. It is the safest size to buy blind.
A6: the true pocket size
A6 fits a jacket pocket or a small shoulder bag, and it is excellent for lists, quick captures and ideas caught on the move. Be realistic about long-form writing, though: a 200-word entry will run across two or three pages, and the narrow width forces you to break lines constantly. Some people love that constraint. Others find it cramped within a week.
A7 and the very small stuff
A7 is note-card territory. Useful for shopping lists, index cards and page markers, rarely comfortable for anything longer than a sentence or two.
B6 and the in-between sizes
B6 is about 125 × 176 mm, a useful compromise between A5 and A6 that fits a coat pocket yet still takes a reasonable paragraph. Watch for brand-specific variations: some makers sell a "B6+" at roughly 125 × 190 mm, and slimmer formats that are narrower but the same height as A5. If you are buying a cover or a refill, trust the millimetre measurements in the specification rather than the label on the front.
B5, and why the label can mislead
ISO B5 is 176 × 250 mm. That extra width compared with A5 is what makes it so pleasant for reading notes, commonplace books and diary entries where you want more than one column of thought on a page. But "B5" is not one size worldwide: Japanese B5 is slightly larger, at about 182 × 257 mm, because it comes from a different standard. Two notebooks both marked B5 can differ by several millimetres, which matters if either needs to fit a specific sleeve, tray or cover.
The same caution applies to familiar brand names. A "large" notebook from a well-known Italian-style maker is roughly A5 at 13 × 21 cm, and its "pocket" version is closer to 9 × 14 cm, which is a touch narrower and taller than true A6.
Paper weight: what gsm actually tells you
Paper is graded in grams per square metre, written as gsm. It measures density rather than quality, but it is the quickest guide to how a page will behave under your pen.
- 70–80 gsm: the standard for inexpensive notebooks. Perfectly good with pencils and ballpoints. Fountain pens, rollerballs and fineliners will show through to the reverse, and a wet nib may bleed outright.
- 90–100 gsm: a comfortable step up. Most fountain pens behave well, show-through is mild, and the notebook stays reasonably thin.
- 100–120 gsm and above: handles markers, brush pens and light washes. Expect noticeably fewer pages for the same bulk, so a 200-page notebook can feel like a hardback.
Two more details worth a glance: a smooth, coated surface suits fine nibs and crisp gel ink, while a slightly textured sheet feels better under pencil. Look for acid-free paper if you want the notebook to still be readable in twenty years.
Page counts, ruling and small print
Pages are not sheets. A "192-page" notebook has 96 sheets, giving you 192 writing surfaces in total, so a page count that looks enormous is often just a standard A5 book. Ruling matters just as much as size: 6 mm lines suit small handwriting and dense notes, 8 mm is kinder to larger script, 5 mm squares work for maths, diagrams and planners, and a dotted grid gives you structure without shouting. Numbered pages, a printed index, a ribbon marker and an elastic closure are the features that turn a notebook into something you can actually find things in later.
Binding types, and how they behave
- Casebound (hardcover, usually sewn): durable, protects the pages and feels substantial. Properly sewn versions open well, though stiff ones resist lying flat.
- Perfect bound (glued paperback): the cheapest option and common on budget A5 notebooks. The spine creases, it refuses to stay open, and pages can work loose with heavy daily use.
- Sewn or lay-flat: opens almost completely flat, which makes writing across a two-page spread easy. The best choice for journals you fill front to back.
- Saddle stitch (staples): fine for thin booklets of up to about 48 pages. Light, cheap and perfectly serviceable for notebooks you finish in a month.
- Spiral or wire-bound: lies flat, folds right back on itself and lets you remove pages. The wire catches on bag linings, and it sits under the heel of your hand, which left-handed writers tend to notice quickly.
- Discbound: pages can be reordered or replaced, but you need the matching punch and a willingness to keep track of the discs.
Matching the size to the job
- Always-carry capture: A6 or A7, softcover, thin enough to disappear in a pocket.
- Daily journal: A5 or B5, sewn binding, 90 gsm or better.
- Study and lecture notes: A4 for diagrams, B5 if you carry it daily. Spiral if you need to hand pages in.
- Planning and mind maps: A4, ideally with a margin for dates and labels.
- Reading notes: B5 for room to quote and comment, A6 for a tally of titles.
- Fit-specific: measure the pocket, bag or cover with a ruler before you order, in millimetres.
How to choose without wasting money
Buy one notebook, not a pack of five. Use it for a fortnight with your usual pen, then check three things: whether the ink shows through on the reverse, whether the spine still sits straight after being opened a hundred times, and whether you actually reached for it. That last point settles most size arguments.
Before ordering a second one, measure twice. Compare the notebook you liked against the one you didn't, note the two sets of millimetre dimensions, and use those as your filter from then on. Once a size, ruling and paper weight have earned their place, buy several at a time and stop thinking about it. The best notebook is the one you keep picking up, and that has very little to do with how it looks on a shelf.
Photo: WikiImages / Pixabay
