Guide
KDP formatting, in the numbers that matter
What Amazon actually requires of a paperback interior, and why each requirement exists. These are the same figures our exporter typesets to.
Checked against KDP’s published requirements on . Amazon changes these occasionally; confirm anything critical against their help pages before you upload.
Trim sizes
The trim size is the finished page size, and it decides everything downstream: how many words fit on a page, how many pages the book runs to, and therefore what gutter it needs. Choose it before you typeset, not after.
| Size | Used for |
|---|---|
| 5" × 8" | Compact. Common for novellas and poetry. |
| 5.5" × 8.5" | The usual trade paperback. A safe default. |
| 6" × 9" | Standard for non-fiction and longer novels. |
Gutter by page count
The gutter is the inside margin. A thicker book loses more of its inside edge into the binding, so the requirement scales with the page count. This is the single commonest reason an interior is rejected, and it is not something you can judge by eye on screen.
| Page count | Minimum gutter |
|---|---|
| 24–150 pages | 0.375" |
| 151–300 pages | 0.5" |
| 301–500 pages | 0.625" |
| 501–700 pages | 0.75" |
| 701–828 pages | 0.875" |
Outside, top and bottom margins must each be at least 0.25", or 0.375" with bleed.
Spine width
The spine is page count times paper thickness. You cannot design a wraparound cover until the interior is final, because a single extra page changes the width. Books under 79 pages cannot carry text on the spine at all.
| Pages | White paper | Cream paper |
|---|---|---|
| 120 | 0.270" | 0.300" |
| 250 | 0.563" | 0.625" |
| 400 | 0.901" | 1.000" |
The other hard limits
- Page count: at least 24, at most 828.
- Font size: at least 7pt, though 10–12pt is what readers expect.
- Bleed, if used: 0.125" added on the top, bottom and outside edges.
- Fonts must be embedded in the PDF. A file that looks right on your machine and has no embedded fonts will be rejected or printed in a substitute.
- Amazon requires you to declare AI-generated content when you publish. That declaration is yours to make.
KDP formatting questions
- What margins does KDP require?
- The inside margin, called the gutter, depends on the page count: 0.375" up to 150 pages, 0.5" up to 300 pages, 0.625" up to 500 pages, 0.75" up to 700 pages, 0.875" up to 828 pages. The outside, top and bottom margins must each be at least 0.25", rising to 0.375" if the interior uses bleed.
- What is a gutter margin and why does it change?
- The gutter is the inside margin, next to the spine. A thicker book curves more at the spine, so more of the inside edge is swallowed by the binding and the text has to start further in. Undersizing the gutter is the commonest reason a KDP interior is rejected.
- How do I calculate spine width?
- Multiply the page count by the paper thickness: 0.002252" a page for white paper and 0.0025" for cream. A 300-page cream paperback has a spine of 0.750". Books under 79 pages cannot carry text on the spine at all.
- What is the minimum page count for a KDP paperback?
- 24 pages, and the maximum is 828 for most trim sizes and paper choices. A manuscript below the minimum has to be set at a larger size or a smaller trim to reach it.
- What font size should a paperback interior use?
- KDP requires at least 7pt, but that is a floor, not a recommendation. Trade paperbacks are typically set between 10 and 12pt; 11pt with generous leading is a safe default for fiction.
- Do I need bleed?
- Only if something on the page is meant to run off the edge — a full-page image or a coloured band. Text-only interiors do not use bleed. With bleed, add 0.125" to the trim on the top, bottom and outside edges, and the outside margin minimum rises to 0.375".
Or skip all of this
The KDP kit picks the trim size, works out the gutter from the final page count, embeds the fonts and writes the cover specification for you.