A5, B5 or A4 for a printed book? It's genuinely hard to answer on the spot. For school handbooks, event booklets or mailers, A5 is common; for company profiles, product catalogues or general publications, more and more clients reach for B5; for portfolios, photo books or art books, A4 shows off photography and design far better. Before you order, narrow it down with three questions: what it's for, how much content it carries, and how far away it will be read.
If you haven't yet decided which kind of publication to print, start with our pre-print checklist, then come back here to weigh up whether A5, B5 or A4 suits you best.
Question one: how will readers pick up the book?
Size choice starts with how the book gets read. A common scenario for Hong Kong SMEs: company profiles, course materials, event programmes or brand proposals that a client holds and reads at their own pace. If that kind of piece needs to be easy to carry, slip into a document folder or take away after a meeting, A5 feels natural — the weight and heft are easy to live with.
If readers will mostly sit and read — in a meeting room, at an exhibition table, at reception or in a school office — both B5 and A4 are worth a look. B5 is smaller than A4 but gives you more layout space than A5; it doesn't feel oversized in the hand and reads a notch more polished than a plain booklet. A4 suits content that needs large images, detailed tables or a formal proposal. To see the available sizes, cover stocks and inner papers first, browse Printing Banana's perfect-bound book printing (from one copy) page, then come back and organise your content structure.
Question two: is your content text-heavy or image-heavy?
If your content is mostly text — course descriptions, service workflows, company background, a simple price list or event details — A5 already reads clearly, as long as you don't cram too many paragraphs onto each page. A5's worst enemy is shrinking down content designed for a larger format: the type, line spacing and images all end up crowded.
If your content mixes product shots, service descriptions, a brand story and a few tables, B5 is the compromise size: more comfortable to lay out than A5, without being as bulky as A4. If it's packed with photos, design work, product images, comparison tables, timelines or large QR codes, A4 is usually the safer bet. Images need room to show detail and tables need column width; force them into A5 and readers may have to zoom in — at which point the print loses its whole point of being clear the moment it's in your hand.
How can you quickly decide between A5, B5 and A4?
Try a simple method: sort your content into "must-read", "supporting" and "can-cut". If a must-read page only needs one topic, two or three paragraphs and a single image, A5 is enough. If you want more presence than A5 without going as formal or large as A4, B5 strikes the balance. If every page has to carry several images, tables, case notes or bilingual (English and Chinese) information, A4 makes it far easier to keep the layout clean.
A5: handheld reading, event booklets, course intros, brand stories, lightweight company profiles.
B5: company profiles, product catalogues, general publications, brand handbooks — not oversized in the hand, but more refined than A5.
A4: proposals, portfolios, detailed product catalogues, school or institutional materials, and content with plenty of images and tables.
Still undecided: mock up one page first and judge readability from the actual type size and image proportions — don't go by the blank dimensions alone.
Page count and binding also change how the size feels
The order options for perfect-bound books are A5 (148 x 210 mm), B5 (176 x 250 mm) and A4 (210 x 297 mm), with inner-page counts running across choices like 4pp + 12pp inner, 4pp + 16pp inner, 4pp + 20pp inner, 4pp + 24pp inner and 4pp + 36pp inner. The more pages, the more obvious the spine and the heft in your hand become; the same content in A5, B5 or A4 will feel different.
With few pages and light content, A5 reads more like an easy little booklet; with a medium page count and a wish for book-like presence without the bulk, B5 feels more like a formal-but-easy-to-hold publication; with more pages and material to present, A4 feels more like a formal document or proposal. If your page count is very low, it's also worth comparing saddle-stitched booklets (small runs), since a thinner booklet doesn't necessarily need perfect binding.
Cover and inner paper change how readers perceive it
Size isn't the only thing that drives the feel of quality. Perfect-bound books can take a 300gsm gloss art paper cover with a choice of matte lamination or gloss lamination; for the inner pages you can pick 128gsm gloss art, 157gsm gloss art, 128gsm matte art, 157gsm matte art or 120gsm woodfree paper as needed. For a brand introduction or proposal, the cover's feel shapes the first impression; for reading-led content, the inner paper's texture and how comfortably it turns matter more.
In short: for punchier image colour, lean towards gloss art paper; for a softer reading feel, consider matte art or woodfree paper. The real choice still has to match what the content is for — don't apply one paper to every job just because it "looks premium".
Once the size is set, re-check the layout before you submit files
After you've settled on A5, B5 or A4, don't judge it from a zoomed view on screen. Before submitting, check the type, images, page numbers, contents page, QR codes and the placement of key information at actual size. A5 especially: type that's too small, line spacing that's too tight or too many images all pile on reading strain; B5 and A4 have more room, but you still need to confirm the balance between images and text.
If you've already started laying out or are getting ready to export a PDF, the next step is checking the spine glue edge, the inner margins of the left and right pages, page numbers, safety margins, bleed and cross-spread images. For the details, see our perfect-bound book file-submission checklist.
FAQ
Should a perfect-bound book be A5, B5 or A4?
If it's mainly for handheld reading, event handouts or mailers, A5 is usually the most convenient. For company profiles, product catalogues or general publications, B5 is the more balanced choice. If the content has plenty of images, tables, proposal material or needs a formal presentation, A4 reads more clearly.
Is A5 too small?
A5 isn't necessarily too small — the key is how much content you put on it. With one key point per page, a sensible amount of images and a clear type size, A5 reads very well; shrink a lot of A4 content straight into A5, though, and you easily end up with type that's too small and a layout that's too crowded.
What content suits B5?
B5 suits company profiles, product catalogues, general publications and brand handbooks. It gives you more layout space than A5 and is a little smaller than A4 — not oversized in the hand, and it reads more refined.
Does the inner paper affect the size choice?
Yes. Thicker or more textured paper gives the book a more solid feel, but at a high page count it also adds thickness and weight. If the content is mainly for long reading sessions, factor in the paper and how comfortably it turns alongside the size.
Can I decide the size before the design is finished?
You can set a direction first, but it's best to mock up one or two pages before confirming. The size name alone isn't enough — the actual type size, image proportions, page count and reading style are the most reliable guides.
Before printing a perfect-bound book, gather the purpose, expected readers, page count, image ratio and where it will be used, then decide between A5, B5 or A4. Once you're set on a direction, check the specs and basic options on Printing Banana's perfect-bound book printing (from one copy) page, then prepare your design files. We deliver across Hong Kong and Macau — WhatsApp us at +852 3001 5678 if you'd like a hand picking a size (English is fine).