Book Sizes
Book sizes are the finished page dimensions after a book is bound and trimmed. British publishing names them, such as A Format, Demy and Royal; American publishing works in inches like 6 by 9.
Crown Quarto measures 189 millimetres wide and 246 millimetres tall.
Dimensions of All Book Sizes
The Book Sizes run from Crown Quarto at 189 × 246 mm to US Mass Market at 106 × 172 mm. Each size, with its typical use:
| Size | mm | cm | inches | Also known as | Common use |
|---|---|---|---|---|---|
| Crown Quarto | 189 × 246 | 18.9 × 24.6 | 7.44 × 9.69 | UK, illustrated non-fiction | illustrated non-fiction, textbooks, manuals |
| Large Print | 178 × 254 | 17.8 × 25.4 | 7.01 × 10 | 7 by 10 in, accessible editions | large-print and accessible editions |
| Royal | 156 × 234 | 15.6 × 23.4 | 6.14 × 9.21 | UK, hardback non-fiction | hardback non-fiction, serious fiction |
| US Trade | 152 × 229 | 15.2 × 22.9 | 5.98 × 9.02 | 6 by 9 in, US default | US paperbacks and hardbacks of most kinds |
| Digest | 140 × 216 | 14.0 × 21.6 | 5.51 × 8.5 | 5.5 by 8.5 in, compact US paperback | compact US paperbacks, workbooks, journals |
| Demy | 138 × 216 | 13.8 × 21.6 | 5.43 × 8.5 | UK, memoir and shorter non-fiction | UK memoir, shorter non-fiction, gift hardbacks |
| Novella | 127 × 203 | 12.7 × 20.3 | 5 × 7.99 | 5 by 8 in, short books | novellas, poetry, short print-on-demand books |
| B Format | 129 × 198 | 12.9 × 19.8 | 5.08 × 7.8 | UK trade paperback | UK literary fiction paperbacks |
| A Format | 110 × 178 | 11.0 × 17.8 | 4.33 × 7.01 | UK rack paperback | UK mass-market rack paperbacks |
| US Mass Market | 106 × 172 | 10.6 × 17.2 | 4.17 × 6.77 | 4.25 by 6.87 in, US rack paperback | US mass-market rack paperbacks |
Dimensions are portrait (short edge first). Centimetre, inch and pixel values are derived by formula, not separate standards.
Common Paperback and Hardback Book Sizes
For a UK paperback, B Format (129 × 198 mm) is the default for literary fiction and A Format (110 × 178 mm) is the smaller rack size sold in supermarkets and airports. UK hardbacks use Demy (138 × 216 mm) or the larger Royal (156 × 234 mm). For a US paperback, 6 × 9 in Trade is standard and 5.5 × 8.5 in Digest is the compact option; the rack paperback is 4.25 × 6.87 in. Non-fiction with tables or figures usually wants Royal or 6 × 9 in for the extra page width.
Book Sizes That Print-on-Demand Services Expect
Amazon KDP and IngramSpark list a fixed set of trims. The safe picks are 5 × 8, 5.5 × 8.5 and 6 × 9 inches, plus the UK A, B, Demy and Royal sizes. 6 × 9 in has the widest distribution and the lowest print cost per page. A smaller trim raises the page count for the same manuscript, which thickens the spine and pushes up the unit price, so the choice is partly an economic one.
Frequently Asked Questions
What is the most common book size?
In the UK, B Format (129 × 198 mm) for paperbacks and Royal (156 × 234 mm) for hardbacks. In the US, 6 × 9 in Trade for paperbacks and 4.25 × 6.87 in Mass Market for rack editions.
What is a trim size?
The size of a finished book page after the bound block is cut on three edges. It is quoted width by height and is the size you hold, not the size of the printing sheet.
What is the difference between A Format and B Format?
A Format is 110 × 178 mm, the small UK rack paperback. B Format is 129 × 198 mm, the larger trade paperback used for most literary fiction.
What book size should I use for KDP?
Pick one KDP lists as a preset: 5 × 8, 5.5 × 8.5 or 6 × 9 inches are the safe choices, with 6 × 9 in the most widely distributed.
Is there a standard novel size?
Not a formal one. A UK novel is usually B Format (129 × 198 mm); a US novel is usually 5.5 × 8.5 or 6 × 9 in. Publishers vary the trim a few millimetres either way.
✓ Member dimensions per Publishing trade size. Centimetre, inch and pixel values derived by formula. Last verified . Editorial Process →