Book sizes: from paperbacks to coffee-table books
There is no ISO standard for books. UK paperbacks come in A-format (110 × 178 mm) and B-format (129 × 198 mm), and many hardbacks are Demy at 138 × 216 mm. The old names folio, quarto and octavo describe how many times a press sheet was folded.
Contents of this page
Common book sizes in the UK
| Name | Size (width × height) | Used for |
|---|---|---|
| A-format paperback | 110 × 178 mm | mass-market paperbacks, crime and genre fiction |
| B-format paperback | 129 × 198 mm | literary fiction, most trade paperbacks |
| C-format paperback | 135 × 216 mm | larger paperbacks, often the first paperback edition |
| Demy | 138 × 216 mm | fiction hardbacks |
| Royal | 156 × 234 mm | non-fiction, biography, hardbacks |
| Crown quarto | 189 × 246 mm | illustrated non-fiction, cookery |
| A4 | 210 × 297 mm | workbooks, manuals, magazines |
These are guide sizes. Publishers set their own and often differ by a few millimetres. Self-publishing services usually offer a fixed list, which in Europe tends to include 125 × 190 mm, 135 × 216 mm, A5, 170 × 240 mm and A4.
Common book sizes in Germany
German publishers use their own customary sizes, which are close to but not the same as the British ones.
| Type | Typical size | Note |
|---|---|---|
| Reclam booklet | about 96 × 148 mm | smaller than A6, the yellow classics edition used in schools |
| Taschenbuch (paperback) | about 115 × 180 to 125 × 190 mm | varies by publisher |
| Novel, hardback | about 135 × 215 mm | a little larger than A5 |
| Non-fiction | about 150 × 230 to 170 × 240 mm | more room for charts |
Where folio, quarto and octavo come from
Books used to be printed on large sheets, which were then folded, cut open and sewn together in sections. The size name tells you how often the sheet was folded and how many leaves it produced.
| Name | Symbol | Folds | Leaves per sheet |
|---|---|---|---|
| Folio | 2° | one | 2 leaves, 4 pages |
| Quarto | 4° | two | 4 leaves, 8 pages |
| Octavo | 8° | three | 8 leaves, 16 pages |
| Duodecimo | 12° | a special fold | 12 leaves, 24 pages |
| Sextodecimo | 16° | four | 16 leaves, 32 pages |
Because sheets came in different sizes, these names said only roughly how big a book actually was. A folio from a large sheet could be enormous, an octavo from a small one tiny. That is why British names such as Crown, Demy and Royal combine the old sheet name with the fold: Crown octavo, Demy octavo, Royal quarto. Libraries later tied the terms to the height of the spine instead.
Book sizes in library catalogues
Many older catalogues and antiquarian booksellers still describe books by these names. In German libraries, the simplified limits were:
- Octavo (8°)
- up to 25 cm
- Quarto (4°)
- 25 to 35 cm
- Folio (2°)
- 35 to 45 cm
- Large folio
- over 45 cm
So if a dealer offers you a book in “8°”, you know it is no taller than about 25 cm. Modern catalogues simply give the height in centimetres.
What matters when printing a book
- Grain direction: it must run parallel to the spine. Otherwise the pages ripple and the book does not open well.
- Gutter margin: with perfect binding, the inner margin has to be wider than the outer one, because part of it disappears into the binding.
- Page count: for sewn and saddle-stitched books, the page count must fit the sheet layout, usually a multiple of 4, 8 or 16.
- Spine width: depends on page count and paper bulk. The printer calculates it before you design the cover.
Frequently asked questions
What size is a B-format paperback?
129 × 198 mm. It is the most common size for trade paperbacks in the UK.
What does 8° mean for books?
Octavo. Historically a sheet folded three times. In libraries it stands for books up to about 25 cm tall.
Is there a standard for book sizes?
No. Book sizes developed over time and differ from publisher to publisher.
Which size should I choose for a self-published book?
For novels, often 125 × 190 mm, B-format or 135 × 216 mm. For non-fiction, 156 × 234 mm or 170 × 240 mm. For workbooks, A4.