Start here: the four decisions
- 1.Trim size — the width × height of the finished book.
- 2.Binding — softcover or hardcover, and how the pages are held together.
- 3.Book block — the interior paper: weight, colour and bulk.
- 4.Cover — the stock and finish: matte, gloss, art paper, special effects.
Take them in that order. Each one narrows the next.
Part 1 · Trim size
How trim size is measured
Trim size is the dimensions of your book’s pages — width × height, always in that order. It’s the size after the printer trims the bound block. Two systems exist side by side: the ISO/metric system (A5, B5 — common in Europe) and the inch system (5×8, 6×9 — standard in the US/UK trade and on the big print-on-demand platforms).
The ISO world: A5, B5 and friends
| Name | Millimeters | Inches | Typical use |
|---|---|---|---|
| A4 | 210 × 297 mm | 8.27 × 11.69 in | Manuals, workbooks, magazines |
| A5 | 148 × 210 mm | 5.83 × 8.27 in | The most common European novel size |
| A6 | 105 × 148 mm | 4.13 × 5.83 in | Pocket books, small gift editions |
| B5 | 176 × 250 mm | 6.93 × 9.84 in | Academic books, larger non-fiction |
| B6 | 125 × 176 mm | 4.92 × 6.93 in | Compact novels, light fiction |
| Regional size | Millimeters | Character |
|---|---|---|
| 12 × 20 cm | 120 × 200 mm | Slim, elegant, literary fiction |
| 13 × 20 cm | 130 × 200 mm | A regional favourite for novels |
| 14 × 20 cm | 140 × 200 mm | Generous novel size |
| 14.5 × 20.5 cm | 145 × 205 mm | Very close to true A5, common trade size |
| 12 × 21 cm | 120 × 210 mm | Tall, narrow, modern look |
| 16 × 24 cm | 160 × 240 mm | Larger non-fiction, illustrated, B5-adjacent |
| 17 × 24 cm | 170 × 240 mm | Textbooks, monographs, art-leaning non-fiction |
The inch world: 5×8, 6×9 and the rest
| Trim (in) | Millimeters | Name / use |
|---|---|---|
| 4.25 × 6.87 | 108 × 175 mm | Mass-market paperback |
| 5 × 8 | 127 × 203 mm | Compact novels, novellas, poetry, self-help |
| 5.25 × 8 | 133 × 203 mm | Fiction, slightly roomier |
| 5.5 × 8.5 | 140 × 216 mm | “Digest” — very common, fiction & non-fiction |
| 6 × 9 | 152 × 229 mm | “Trade” — the US default |
| 7 × 10 | 178 × 254 mm | Textbooks, workbooks, illustrated non-fiction |
| 8.5 × 8.5 | 216 × 216 mm | Square — children’s & photo books |
| 8.5 × 11 | 216 × 279 mm | Letter — manuals, activity books |
Trim sizes by genre
- Literary & general fiction5×8, 5.25×8, 5.5×8.5, 6×9 · or A5, 13×20 cm
- Mass-market / genre fiction4.25×6.87, 5×8 · or 12×20 cm
- Non-fiction & memoir5.5×8.5, 6×9 · or A5, 14.5×20.5 cm
- Academic & textbooks7×10, B5, 17×24 cm
- Poetry5×8, 5.25×8, custom slim · 12×20 cm
- Children’s picture books8.5×8.5 (square), 8×10, 7×10
- Coffee-table, art & photography8.5×11 and up, often square or landscape
What the platforms actually offer
Amazon KDP — ~16 standard paperback trims plus custom (width 4–8.5 in, height 6–11.69 in); 5 hardcover sizes (case laminate). Covers on 80 lb (220 gsm) stock, glossy or matte. Official spec ↗
IngramSpark — wide range of paperback & hardcover trims, Pocket to large; hardcover with case laminate or dust jacket; widest distribution reach. Official spec ↗
Barnes & Noble Press — paperback & hardcover, 4.25×7 up to 11×8.5; min 18 / max 800 pages. A PDF that passes KDP usually passes B&N too. Official spec ↗
What real publishers use
- Penguin / Penguin Classics — compact paperbacks ≈129 × 198 mm.
- Penguin Random House — hardcover firsts 6 × 9 in; trade paperbacks 5.5 × 8.25 to 6 × 9.
- HarperCollins — trade paperbacks 5.31 × 8 / 6 × 9.
- Macmillan / Picador — literary paperbacks ≈ B-format (129 × 198 mm).
- UK standards — A-format 110×178, B-format 129×198, C-format 135×216.
- Oxford / Cambridge — Royal (156 × 234 mm) and Demy (138 × 216 mm).
- European trade — A5 and the 13×20 / 14.5×20.5 cm family; B5 / 16–17×24 cm for non-fiction.
Part 2 · Softcover or hardcover
Softcover (paperback)
A flexible card cover, same size as the pages. The default for most fiction and non-fiction: cheaper per copy, lighter to ship, ideal for print-on-demand. Best for novels, genre fiction, most non-fiction and poetry.
Hardcover (case-bound)
A rigid board case, slightly larger than the pages, sometimes with a dust jacket. Signals permanence and value — gift and collector editions, premium non-fiction, children’s. Variations: case laminate (artwork on the board), cloth/clothbound (often with foil), and dust jacket. Many authors release both — a paperback for reach, a hardcover for collectors.
Binding methods in plain terms
- Perfect binding — pages glued into a flat-spined paperback. The standard; needs ~48+ pages to carry spine text.
- Case binding (Smyth-sewn or glued) — signatures bound into a hard case; the sewn version is the most durable binding there is.
- Saddle stitch — folded sheets stapled at the spine. For booklets, zines, chapbooks.
- Spiral / wire-o — for workbooks and cookbooks that need to lie flat.
Part 3 · The book block (interior paper)
Paper weight (GSM) without the confusion
GSM = grams per square metre. Higher GSM = thicker, heavier, more opaque. The honest ranges for book interiors:
| GSM | US approx | What it is | Use |
|---|---|---|---|
| 56–60 gsm | 38–40 lb | Groundwood / mass-market | Thin paperbacks; more show-through |
| 70 gsm | ~50 lb | Standard cream/white offset | Very common for novels — regional default |
| 80 gsm | ~55–60 lb | Standard offset (woodfree) | The sweet spot for most books |
| 90–100 gsm | 60–70 lb | Heavier offset | Premium fiction, illustrated text |
| 115–135 gsm | 80–100 lb | Coated (matte/gloss) | Books with many images / graphics |
| 150–200 gsm | 100–150 lb | Heavy coated | Art, photography, coffee-table |
Cream vs white vs groundwood
Cream (ivory) — warm, easier on the eyes over long reading, feels literary; the traditional choice for fiction. White — brighter, higher contrast; better for non-fiction, textbooks and anything with charts or B/W photos. Groundwood — lower-cost, lighter, more show-through. Rule of thumb: cream for novels, white for non-fiction and image-heavy books.
Bulky, volume and why two 80 gsm papers differ
Two papers of the same GSM can have different thickness — that’s bulk (or volume). A bulky stock is thicker for its weight, so a short book gets a more substantial spine without changing the writing; a low-bulk paper keeps a long book from becoming a brick. A real, professional lever.
Show-through, opacity and reading comfort
Show-through is when text from the back of a page is faintly visible through the front — it reads as cheap and tires the eye. Higher GSM and opacity reduce it. For text-only books, 70–80 gsm offset handles it well; for heavy ink coverage, step up the weight. (Solid black text should be 100% black, not built from CMYK — we handle that in prepress.)
Part 4 · The cover (stock and finish)
Covers are almost always printed on heavier coated stock — for paperbacks, around 240–300 gsm card, then laminated. The laminate decides the feel.
Matte, gloss and soft-touch
- Matte — minimal sheen, smooth, understated, modern; hides fingerprints. The current default for a lot of trade fiction.
- Gloss — shiny, makes colours pop and blacks deeper; great for artwork, children’s and genre covers.
- Soft-touch — a matte film with a velvety hand-feel; distinctly premium, common on upmarket fiction.
Art paper (kunstdruk) and coatings
Kunstdruk is coated art paper — smooth, clay-coated stock that reproduces images sharply, in matte- or gloss-coated versions. Used for covers (heavy art card, laminated) and for the interiors of image-heavy books (115–170 gsm coated). Coated = sharp images, vivid colour; uncoated (offset/woodfree) = natural, easy on the eye, takes pen — best for text.
Premium finishes: foil, emboss, spot UV
- Foil stamping — metallic or coloured foil pressed into the title. Signals premium instantly.
- Embossing / debossing — raising or pressing-in part of the design for a tactile effect.
- Spot UV — glossy varnish on selected areas over a matte cover, catching the light.
- Sprayed / coloured edges — colour on the trimmed page edges; the darling of collector editions and BookTok.
Part 5 · Putting it together
Recommended recipes by book type
A quick spec checklist
- 1. Trim size — pick from the tables, or give us the genre and we’ll suggest.
- 2. Binding — softcover, hardcover, or both.
- 3. Interior paper — weight (70/80 gsm…), colour (cream/white), any bulk preference.
- 4. Cover finish — matte, gloss or soft-touch; any foil/emboss/spot-UV ambition.
- 5. Where you’ll print — KDP, IngramSpark, B&N Press, a local/offset house, or undecided.
- 6. Page count & images — rough length, and whether the interior has photos or graphics.
Common questions
What is the most common book trim size?+
In the US, 6 × 9 inches (152 × 229 mm) for trade; in Europe, A5 (148 × 210 mm). Both are safe defaults for novels and non-fiction.
What does GSM mean for book paper?+
GSM is grams per square metre — paper weight. Most novels use 70–80 gsm offset paper; image-heavy books use heavier coated stock at 115–170 gsm.
Should I use cream or white interior paper?+
Cream is warmer and easier to read for fiction; white gives higher contrast for non-fiction, textbooks and anything with charts or photos.
What is the difference between matte and gloss covers?+
Matte has minimal sheen, feels premium and hides fingerprints; gloss is shiny and makes colours and artwork pop. Soft-touch is a velvety premium matte.
What is kunstdruk paper?+
Kunstdruk is coated art paper — smooth, clay-coated stock that reproduces images sharply. Used for covers and for the interiors of photo and art books, in matte or gloss.