Home Resources Trim size comparison
Free toolBook trim size comparison
Paperback and hardcover trim sizes drawn at true scale against each other, with what your own word count runs to in each. The trim decides the page count, and the page count decides the spine and the print cost.
| Trim | Pages | Words a page | Spine, cream | What it is for |
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How the trim sizes compare
The rectangles are drawn to scale against each other, so the strip shows the real difference in proportion. A mass market page is narrower than a 6 by 9, not just shorter.
Page counts use the same model as the words to printed pages calculator: standard margins, normal leading, mixed prose, thirty chapters, ten pages of matter, rounded up to a multiple of four. Spine widths are the page count times 0.0025 inches, which is KDP's figure for black ink on cream.
Hardcover has two constraints a paperback does not. It comes in five sizes rather than sixteen, and it has to land between 75 and 550 pages, so a very long novel cannot be a KDP hardcover at all.
Galley sets the manuscript on the real page rather than on a letter sheet you resize at export, so the trim is a decision you make once and see for the whole draft. More in book design.
For working things out, not for signing anything. Printers and retailers set their own rates and specifications, change them without notice, and none of them is affiliated with me or with Galley. I checked these figures by hand in August 2026 against KDP's trim size list . Confirm on the official page before you commit money to a price, a print run or a contract.
Questions
What is the best trim size for a novel?
For self-publishing, 6 by 9 inches. It is the size readers expect from a paperback novel, every printer supports it, and it holds the most words per page of the common trims, which keeps the print cost down. Pick 5.06 by 7.81 if you want the book to feel like a British paperback.
Does trim size change my page count?
Heavily. The same 90,000 words runs to about 290 pages at 6 by 9 and about 450 at mass market size. That changes the spine width, the print cost, and the shelf presence of the finished book.
What trim sizes does a hardcover come in?
On Amazon KDP, five: 5.5 by 8.5, 6 by 9, 6.14 by 9.21, 7 by 10 and 8.25 by 11 inches. Hardcovers also have to be between 75 and 550 pages, which rules out both very short and very long books.
Should the hardcover match the paperback?
It is easier if it does. Same trim means the same interior file and the same page count, so the two editions stay in step and you only lay the book out once. Different trims mean two layouts, two page counts and two spine widths.
Can I change trim size later?
Yes, but the whole interior reflows and the page count moves, so the cover spine has to be rebuilt. Choose the trim before you commission a cover, not after.
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