---
title: "KDP Paperback Specs That Actually Matter — Margins, Bleed, Spine & Paper | PuzzleBindery"
description: "The Amazon KDP paperback specs that get files rejected: gutter by page count, bleed on interiors vs covers, spine width per paper stock, maximum pages per paper, barcode clearance. Written plainly, with the numbers."
canonical_url: "https://puzzlebindery.com/kdp-specs"
source: "PuzzleBindery"
---
# The KDP paperback specs that actually matter

Amazon documents all of this, but across a dozen help pages, and the numbers that cause rejections are the ones buried deepest. This is the short version, with the actual figures. Every number here is one the PuzzleBindery export engine uses to build files that pass.

## Page count comes first

Almost everything else depends on it: the gutter steps with page count, and the spine width is page count times a per-paper multiplier. Settle the page count before you size anything else.

-   **Minimum 24 pages**, for every trim and every paper.
-   **The page count must be even.** Add a blank page rather than letting the printer decide for you.
-   The maximum **depends on your paper**. See the table below — this one catches people out.

## Paper stock: spine width and page limits

| Paper | Spine multiplier (inches per page) | Maximum pages |
| --- | --- | --- |
| White | 0.002252 | 828 |
| Cream | 0.0025 | 776 |
| Groundwood | 0.00235 | 812 |
| Premium colour | 0.002347 | 828 |

Spine width = page count × the multiplier. A 120-page book on white paper is `120 × 0.002252 = 0.270"`.

**The trap:** 828 pages is a _white paper_ limit. Cream tops out lower, so a 790-page book that is perfectly fine on white simply cannot be printed on cream.

## Interior margins

### The gutter steps with page count

| Page count | Minimum gutter (inside margin) |
| --- | --- |
| 24 – 150 | 0.375" |
| 151 – 300 | 0.500" |
| 301 – 500 | 0.625" |
| 501 – 700 | 0.750" |
| 701 and up | 0.875" |

The gutter alternates sides: it sits on the left of a right-hand page and the right of a left-hand page. If your margins are symmetric, the text on half the book drifts toward the binding — and a thick book swallows it.

### Outside, top and bottom

-   Without bleed: at least `0.25"` on the outside, top and bottom.
-   With bleed: at least `0.375"`.

## Bleed works differently on interiors and covers

**Interiors:** bleed goes on the top, bottom and outside edge — _never_ the binding edge. Your PDF page becomes `trim width + 0.125"` wide by `trim height + 0.25"` tall.  
  
**Covers:** bleed goes all the way round. The full wrap is `(trim width × 2) + spine + 0.25"` by `trim height + 0.25"`.

Bleed is all-or-nothing per file. If one page bleeds, the whole interior has to be set up for bleed — you cannot mix.

## Cover details people get wrong

-   **Spine text needs more than 79 pages.** At 79 or fewer, KDP prints no spine text at all. Even when you qualify, leave about `1/16"` clear either side of the text, because the trim shifts slightly between copies.
-   **The barcode area is 2" × 1.2"**, and it sits `0.25"` in from the bottom and side _trim_ lines. On a cover with bleed that works out to `0.375"` from the edge of your file. Measuring from the file edge instead of the trim is the usual mistake.
-   Keep anything you care about at least `0.25"` inside the trim line. The cut has a tolerance and it is bigger than people expect.

## The trim sizes KDP prints

| Trim | Typically used for |
| --- | --- |
| 5" × 8" | Pocket size — small grids only |
| 5.25" × 8" | Compact paperback |
| 5.5" × 8.5" | Common digest size |
| 6" × 9" | Most popular for word search and sudoku |
| 6.14" × 9.21" | Trade paperback |
| 6.69" × 9.61" | Roomier trade size |
| 7" × 10" | Roomier grids, still compact |
| 7.44" × 9.69" | Textbook proportions |
| 7.5" × 9.25" | Workbook size |
| 8" × 10" | Kids activity books |
| 8.25" × 8.25" | Square — activity and kids |
| 8.5" × 8.5" | Large square |
| 8.5" × 11" | Large print and letter size |

**Choose the size for the destination.** A4 and US Letter are useful for home-printable packs. For a KDP book, check the current supported trim dimensions for your binding, ink and paper choice before exporting. Do not assume a printable worksheet size is the right book trim.

## A checklist before you upload

-   Page count is even, at least 24, and within your paper's maximum
-   Gutter matches the tier for your _final_ page count, and alternates sides
-   Bleed applied to the whole interior, or to none of it
-   Spine width calculated from the final page count and the paper you actually selected
-   No spine text under 80 pages
-   Barcode area left clear, measured from the trim rather than the file edge
-   Fonts embedded and the PDF flattened

**Tools on this site:** [Spine width calculator](https://puzzlebindery.com/cover-calculator) · [Puzzle book studio](https://puzzlebindery.com/app) · [Longer guide to margins and bleed](https://puzzlebindery.com/blog/kdp-margins-bleed-and-spine-explained) · [All publishing guides](https://puzzlebindery.com/blog/)