The common sizes.
Sizes are width by height. These four cover most paperbacks in the United States, and print-on-demand services everywhere.
Mass-market in
108 × 175 mm
Small, cheap paperbacks, mostly from traditional publishers.
5 × 8 in
127 × 203 mm
Compact fiction: novels, novellas, collections.
5.5 × 8.5 in
140 × 216 mm
Fiction and non-fiction alike; memoir, literary fiction.
6 × 9 in
152 × 229 mm
The most common trade size; non-fiction and longer novels.
Sizes in millimetres.
Publishers in the UK and Australia have their own names for the sizes they use most:
- A-format
- 110 × 178 mm. The small mass-market paperback.
- B-format
- 129 × 198 mm. The usual size for paperback fiction.
- Demy
- 138 × 216 mm. Hardbacks and larger “trade” paperbacks.
- Royal
- 156 × 234 mm. Non-fiction, especially illustrated or reference books.
Print-on-demand services mostly work in inches. 5 × 8 (127 × 203 mm) and 5.25 × 8 sit close to B-format, and 5.5 × 8.5 close to Demy.
How to choose.
- Look at your shelf. Find three recent books like yours and measure them.
- Fiction tends to be smaller. 5 × 8, 5.25 × 8 or 5.5 × 8.5 feel like a novel in the hand.
- Non-fiction tends to be larger. 6 × 9 leaves room for headings, lists and the odd table.
- Mind the page count. The same words on a smaller page make more pages, a thicker spine and a higher printing cost. A long novel at 5 × 8 can turn into a brick; 6 × 9 brings the page count down.
- Check your printer. Not every service offers every size, and some sizes cost less to print or distribute more widely.
Margins and the gutter.
The inside margin, where pages meet the spine, is called the gutter. The thicker the book, the more of each page disappears into the binding, so printers ask for a wider gutter as the page count rises. At the time of writing, Amazon KDP asks for at least these inside margins:
- 24 to 150 pages
- 0.375 in (9.6 mm)
- 151 to 300 pages
- 0.5 in (12.7 mm)
- 301 to 500 pages
- 0.625 in (15.9 mm)
- 501 to 700 pages
- 0.75 in (19.1 mm)
- 701 to 828 pages
- 0.875 in (22.3 mm)
Outside margins need to be at least 0.25 in (6.4 mm), or 0.375 in (9.6 mm) if your pages bleed. These are minimums; most books look better with more. Check your printer’s current requirements before you upload: KDP’s trim size and margins guide, and IngramSpark’s file creation guide, are the usual references.
⌥⌘E
In Wryte
Doing it in Wryte.
Choose File ▸ Export and start from Paperback. Wryte makes a print-ready PDF at 5 × 8, 5.5 × 8.5 or 6 × 9 inches, and the preview shows the pages as you change the settings. It sets:
- mirrored margins, with inside margins of 0.75 in at 5 × 8, about 0.8 in at 5.5 × 8.5 and 0.875 in at 6 × 9, comfortably above KDP’s minimums for books up to 700 pages, and up to 828 pages at 6 × 9;
- running heads and centred page numbers;
- chapters that open on a right-hand page;
- a Classic style in Baskerville, or a Modern one in Charter with Avenir Next headings.
The PDF is the inside of the book. The cover, with its spine and back, comes from your designer or your printer’s cover tool.