Home › Blog › KDP margins, bleed and spine
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.
The 62-page word-search example 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.
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, or use the page-count planner to compare layouts.
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.
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 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.
Use KDP’s cover calculator and template 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.
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.
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.
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.
Our free 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, all of it is derived from your live book, but you should export the interior and cover together again after making changes.
Gutter tiers, the interior-versus-cover bleed difference, spine width per paper stock and the page ceilings nobody mentions. I’ll send the guide and a note when Amazon changes the rules.
Free, and you can leave any time. No spam, ever.