Short answer. KDP hardcover margins follow the same table as paperback. The gutter is 0.375 inch up to 150 pages, 0.5 inch to 300, 0.625 inch to 500 and 0.75 inch to 550. The outside margins are at least 0.25 inch. What changes is usually the trim size, and a new trim moves the page count and every page end.
Key points
- KDP publishes one margin table. It does not give a separate hardcover table.
- Hardcovers run 75 to 550 pages, so four gutter bands apply.
- If your paperback trim is also a hardcover trim and the page count is 75 to 550, the same interior can work for both.
- A 5 x 8, 5.06 x 7.81 or 5.25 x 8 paperback has to be reset, because those trims are paperback only.
- Our hardcover interior from your paperback resets the trim and gutter and rechecks every page end.
What are the KDP hardcover margins?
From KDP's Set Trim Size, Bleed, and Margins page, read on 13 October 2026, for the page counts a hardcover can have:
| Page count | Inside (gutter) | Outside, no bleed | Outside, with bleed |
|---|---|---|---|
| 75 to 150 | 0.375 in | at least 0.25 in | at least 0.375 in |
| 151 to 300 | 0.5 in | at least 0.25 in | at least 0.375 in |
| 301 to 500 | 0.625 in | at least 0.25 in | at least 0.375 in |
| 501 to 550 | 0.75 in | at least 0.25 in | at least 0.375 in |
The full table runs on to 828 pages, but a hardcover stops at 550. The same page lists the five hardcover trims, and KDP's fix page for paperback and hardcover files points to these margin rules.
So why do people say hardcover margins are different?
Because the file usually has to change for another reason. The margins rule is the same, but the trim may not be.
Three of the common small paperback trims are not offered in hardcover: 5 x 8, 5.06 x 7.81 and 5.25 x 8. The smallest hardcover is 5.5 x 8.5. When the trim gets bigger, each page holds more words, the page count falls, and the gutter band may change with it.
When can I use the same interior for both?
KDP says that if your manuscript fits both the paperback and the hardcover requirements, you can upload an interior with the same measurements for both. Run three checks:
- The trim is one of 5.5 x 8.5, 6 x 9, 6.14 x 9.21, 7 x 10 or 8.25 x 11.
- The page count is between 75 and 550.
- The ISBN on the copyright page is changed to the hardcover's.
If all three pass, your margins already pass too. A 6 x 9 paperback of 280 pages with a 0.5 inch gutter is a hardcover-ready interior once the ISBN line is changed.
What happens to the gutter when I reset a 5 x 8 book?
The page count drops, so the gutter band can drop with it. A book that sat at 320 pages in 5 x 8 needs 0.625 inch. Reset to 6 x 9, it may fall under 300 pages, where the minimum is 0.5 inch.
You may keep the bigger gutter. The table gives minimums, not exact values. What you cannot do is keep the 5 x 8 PDF and hope. KDP checks that the page size matches the trim you picked.
The fix we do for this: we make the hardcover interior from your paperback file, reset the page size and gutter for KDP's hardcover rules, and recheck every page end before we export. Send us a chapter for a free formatted sample.
How much margin do we actually use?
More than the minimum. The sample on our hardcover page, a 6 x 9 chapter of The Great Gatsby we set and checked on 13 October 2026, uses a 0.75 inch gutter and a 0.6 inch outside margin with 34 lines a page. The PDF is 432 x 648 points, exactly 6 x 9 inches, and all four fonts show as embedded in pdffonts.
The minimums keep KDP from rejecting the file. A wider margin keeps the text off the edge when a reader holds the book open.
Do italics or text boxes cause margin errors in hardcover files?
They can, the same as in paperback. KDP's fix page says italic text can overhang the margin, and suggests margins a little bigger than the minimum. It also flags empty text boxes and hidden spaces that sit outside the margins. Our post on why KDP keeps rejecting your book covers the full list of interior errors.
What else do authors ask about KDP hardcover margins?
No. The minimum is set by page count and is the same table for both.
At least 0.5 inch.
KDP's margin table has a with-bleed column at 0.375 inch outside. If your paperback uses bleed, keep it in the hardcover file at the hardcover trim.
Only the ISBN on the copyright page, if the page count is 75 to 550.
In our post on KDP margins by page count for 6x9, 5x8 and 5.5x8.5.
What should you do next?
Check your trim against the five hardcover sizes. If it is on the list, change the ISBN and upload. If it is not, the interior needs a reset, which is what our hardcover from paperback service does for $59 in 3 business days with a paperback order.
