When you hold a book you like, you are reacting to dozens of small physical decisions. Making them well is part of what makes a self-published book feel professional. Here are the main ones.
Trim size
Trim size is the finished page size of the book. A few tips:
- Follow your genre. Novels and memoirs usually sit in the familiar trade paperback sizes, such as 5 x 8 inches, 5.5 x 8.5 inches or 6 x 9 inches, or their metric equivalents. Larger sizes suit workbooks, cookery books and picture books.
- Check what your platform supports. KDP and IngramSpark each offer a defined list of sizes, and not every size is available in every format.
- Think about page count. A given amount of text will run to a different number of pages at each size, which affects the cost, the thickness of the book and the price you need to charge.
Margins and the gutter
The gutter is the inner margin next to the spine. It needs to be wider than the outer margin so that the text does not disappear into the binding, and thicker books need a wider gutter. Outer, top and bottom margins should be comfortable, because crowded pages look amateur.
Type
Choose a readable typeface designed for long text, and set it at a size that suits it, commonly somewhere between 10 and 12 points for the body of a book. Check the line spacing and the length of the lines. If it is hard to read at arm's length, it is wrong.
Paper
- Cream paper is warmer and softer and is common for fiction and narrative non-fiction.
- White paper has crisper contrast and suits colour interiors, illustrations and technical or instructional books.
Most print-on-demand platforms offer both for black-and-white interiors, but check which options are available for the format you want.
Cover finish
Platforms usually offer a matte or a gloss finish for the cover.
- Matte has a soft, modern look and hides fingerprints.
- Gloss gives colours more punch, which can suit children's books and bold designs.
The spine
Spine width depends on the page count and the paper, so the cover design cannot be finished until the interior is. Your designer needs the final page count and the platform's spine calculator or template.
Front and back matter
A properly formatted book includes the elements readers expect: a title page, a copyright page (with the ISBN), a contents page where it helps, and an "about the author" page at the end. These contribute a great deal to the finished feel.
Matching size to genre and price
Look at three or four recent books like yours and measure them. Genre readers have expectations: a thriller that is much taller than its competitors can look out of place, and a poetry collection in a tiny format can look slight. Then check the page count at that size, because the page count affects both the printing cost and the spine width. Our guide to paperback, hardback or eBook explains how the formats compare, and KDP or IngramSpark explains which sizes each platform supports.
Once the interior is final, tell your designer the exact page count so that the cover and spine are right. Our back cover checklist shows what goes on the rest of the wrap.
Why it matters
None of these choices is complicated, but they interact, and a professional typesetter makes them together. See our interior layout design service.
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