---
title: "KDP Margins, Bleed and Spine Width, Explained Properly (2026)"
description: "Every number in Amazon KDP's print specification, explained: gutter tiers by page count, outer margins, bleed dimensions, spine width formulas for white and cream paper, and why covers get rejected."
canonical_url: "https://puzzlebindery.com/blog/kdp-margins-bleed-and-spine-explained"
source: "PuzzleBindery"
---
[Home](https://puzzlebindery.com/) › [Blog](https://puzzlebindery.com/) › KDP margins, bleed and spine

# KDP Margins, Bleed and Spine Width, Explained Properly

Use your final page count, selected paper and trim size to check the gutter, bleed and cover dimensions. Here is a worked example and the official KDP sources to verify your files.

Updated 29 September 2026 · By PuzzleBindery

### Check these measurements against a real book

The [62-page word-search example PDF](https://puzzlebindery.com/downloads/word-search-book-proof.pdf) contains 50 puzzles and matching answers at 6 × 9 inches. Inspect the inner margins and solution pages, then compare them with the rules below.

[Start the 50-puzzle draft](https://puzzlebindery.com/app#book/wordsearch50)

Edit the draft and export a free watermarked proof. Check the final page count before making its cover. [See the full workflow and licence details](https://puzzlebindery.com/word-search-book-generator), or use the [page-count planner](https://puzzlebindery.com/puzzle-book-page-count-calculator) to compare layouts.

## The gutter, and why it grows

The **gutter** is the inside margin — the one against the binding. It is larger than the outer margin because a thicker book curves more sharply at the spine, swallowing more of the page. A 600-page book physically cannot be opened flat, so Amazon demands more clearance.

| Page count | Minimum gutter |
| --- | --- |
| 24 – 150 | 0.375" |
| 151 – 300 | 0.5" |
| 301 – 500 | 0.625" |
| 501 – 700 | 0.75" |
| 701 – 828 | 0.875" |

Two consequences people miss. First, these are **tiers**: adding one puzzle that pushes you from 150 to 151 pages increases your required gutter by an eighth of an inch across the entire book. Second, the gutter **alternates** — left on odd pages, right on even pages — because odd pages are right-hand pages. Software that applies a fixed left margin to every page produces a book where every second page runs into the spine.

## Outer margins

Top, bottom and the outside edge need at least **0.25"** without bleed, or **0.375"** with bleed. Anything closer risks being trimmed off, because guillotines have tolerance.

This is also why page numbers cause trouble: designers place them a comfortable-looking distance from the edge and end up inside the danger zone. Keep any live element — text, page numbers, rules — at least a quarter inch from the trim line.

## Bleed

Bleed is extra artwork extending **beyond** the trim line, so that when the trimmer cuts slightly off-centre there is no white sliver at the edge.

-   **Interiors:** only needed if artwork touches the page edge. Most puzzle books don't need it. If you do use it, your page size grows by 0.125" on the outer edge and 0.125" top and bottom.
-   **Covers:** always require bleed — 0.125" on all four outer edges, which is why cover width includes an extra 0.25" in total.

## Spine width

Use [KDP’s cover calculator and template](https://kdp.amazon.com/cover-calculator) for your final configuration. For a planning estimate, multiply the page count by the appropriate paper factor:

| Paper & ink | Inches per page |
| --- | --- |
| Black ink, white paper | 0.002252 |
| Black ink, cream paper | 0.0025 |
| Premium colour, white paper | 0.002347 |

Multiply by your final page count. A 120-page book on white paper: `120 × 0.002252 = 0.2702"`. On cream, the same book has a 0.3" spine — cream stock is thicker, and switching paper after you've made the cover is a classic self-inflicted rejection.

### The full cover

-   **Width** = (trim width × 2) + spine + 0.25"
-   **Height** = trim height + 0.25"

So a 6×9 book of 120 pages on white paper needs a cover exactly **12.520" × 9.250"**, or 3756 × 2775 pixels at 300 DPI.

## Spine text: more than 79 pages

KDP only prints text on the spine for books with **more than 79 pages**. Below that the spine is too narrow: binding drift of up to 0.0625" would pull your title round onto the front or back cover.

A related trick worth knowing — on any thin book, make the spine **the same colour as the covers**. If it's a contrasting colour and the wrap drifts even slightly, you get an obvious off-centre stripe. Matching colour makes drift invisible.

## The barcode zone

Amazon prints a barcode in a **2" × 1.2"** box at the bottom-right of your back cover. Anything you put there — blurb, logo, author photo — gets covered. Leave it empty, and ideally leave it light so the barcode scans reliably.

## Three checks before uploading

1.  **Spine width calculated for the wrong page count or paper.** It changes every time your interior changes.
2.  **Live text inside the 0.25" margin.** Usually page numbers.
3.  **Odd page count.** KDP rounds an odd manuscript page count up to an even count. Use that final count for your spine calculation; an odd uploaded manuscript is not by itself proof of rejection.

### Or let the numbers take care of themselves

Our [free calculator](https://puzzlebindery.com/cover-calculator) works out spine width, full cover dimensions and the required gutter for the supported trim, page-count and paper options — and hands you a blank template with every zone marked. And in [the Studio](https://puzzlebindery.com/app), all of it is derived from your live book, but you should export the interior and cover together again after making changes.

[Open the calculator →](https://puzzlebindery.com/cover-calculator)