The binding you can use is decided mostly by page count and trim size, and the limits are narrower for hardcover than most people expect. At Amazon KDP a hardcover must be 75 to 550 pages in one of five trim sizes; a paperback can be 24 to 828 pages in far more.
A 700-page paperback cannot be reissued as a KDP hardcover at all. Neither can a 60-page one.
KDP: The Two Sets of Limits
| Paperback | Hardcover | |
|---|---|---|
| Page range, black on white | 24 to 828 | 75 to 550 |
| Black on cream | 24 to 776 | 75 to 550 |
| Groundwood | 24 to 812 | not offered |
| Standard colour | 72 to 600 | not available |
| Premium colour | 24 to 828 | 75 to 550 |
| Trim sizes | many, plus custom | five only |
| Custom trim | yes | no |
The five hardcover trims are 5.5 by 8.5, 6 by 9, 6.14 by 9.21, 7 by 10, and 8.25 by 11 inches. Anything smaller has no hardcover option at KDP at all, which is why 5 by 8 and 5.25 by 8 are paperback-only there.
Custom trim is paperback-only: KDP states that "For paperbacks, you can also enter your own custom trim size. Width must be within 4"-8.5" (10.16-21.59 cm). Height must be within 6"-11.69" (15.24-29.69 cm)." There is no equivalent for hardcover.
Worth flagging how the 75-page floor is published: it appears only as the page-range column of the hardcover trim table, repeated for every size and paper. There is no prose sentence stating it anywhere, which is why so much advice gets it wrong.
IngramSpark and Lulu Disagree With KDP, and With Each Other
IngramSpark applies no hardcover penalty at all. Its minimum is 18 pages for every paper and both bindings, with hardcover ceilings of 840 and perfect-bound ceilings from 900 to 1200 depending on stock. A 30-page hardcover is possible there and impossible at KDP.
Lulu inverts the relationship entirely:
"Paperback books require a minimum of 32 interior pages. Hardcover books require a minimum of 24 interior pages."
Lulu's hardcover minimum is lower than its paperback minimum, the opposite of KDP. There is no deeper principle here; these are binding-line constraints, and no amount of reasoning will reconcile them. Check the platform you are actually using.
What Is Physically Different
A paperback is a text block glued into a laminated cover. A hardcover wraps that block around rigid boards, which introduces measurements a paperback never has.
Board size is not trim size. IngramSpark publishes the only board formula I could find from any platform:
"The board size for a custom case laminate is calculated by subtracting: .185" (5mm) from the trim size width and adding: .25" (6mm) to the trim size height."
Note the asymmetry: the board is narrower than the page but taller. It overhangs at head and foot by an eighth of an inch each, while the fore-edge overhang is offset by the hinge setback.
The hinge is a real allowance. IngramSpark's cover diagram labels a 0.5 inch (13 mm) gutter and hinge zone on each side of the spine, and warns about what happens there: "Casebound books contain an area where the spine board is connected to the front and back cover boards. This area will be pliable and have a slight indention. To ensure cover elements are not obscured by the indention, please keep all important elements outside of the gutter bleed area."
KDP's equivalent is an artwork setback rather than a stated joint width: "There's a 0.4" (10 mm) space between the spine and safe area on the front and back covers."
The cover wraps and is glued inside. KDP: "Cover file images should extend 0.51" (15 mm) past the edge of the front cover. This area will wrap around the case board and be glued to the inside cover."
Dust jackets add flaps. IngramSpark: "Dust jackets have an additional 3.25" (82.55mm) area that wraps around the hardcover book", plus "a 0.25" (6mm) wrap area between the front/back covers and flaps."
Cover Types Available
- KDP: case laminate only, printed directly onto the case. No dust jacket appears anywhere in its hardcover documentation.
- IngramSpark: case laminate, Digital Cloth in blue or grey, and jacketed versions of either. "Where available, Jacketed Covers can be set-up with either Case Laminate or Digital Cloth Covers."
- Blurb: ImageWrap hardcover, or Linen hardcover with a dust jacket.
So if you want a cloth-bound book, or a dust jacket, IngramSpark is the route.
Margins Are Not Adjusted for the Binding
A detail worth knowing, because it is counterintuitive. KDP publishes one margin table, not split by binding. There is no separate hardcover gutter table and no added allowance for the hinge. A hardcover falls in the 501 to 700 band at 0.75 inches of gutter like any other book of that length. The full table is in US print on demand book requirements.
Since the boards and hinge do consume some readable width at the spine, treating the published minimum as a floor rather than a target is worth doing on a hardcover specifically.
The Cost Difference Is Almost All Fixed
KDP publishes both cost formulas as "Fixed cost + (page count * per page cost) = printing cost". Comparing them on Amazon.com, black ink, regular trim:
| Fixed | Per page | |
|---|---|---|
| Paperback, 110 to 828 pages | $1.00 | $0.012 |
| Hardcover, 110 to 550 pages | $5.65 | $0.012 |
The per-page rate is identical. The entire hardcover premium is $4.65 per unit in the fixed cost, which is the case binding. That is the single most useful number for deciding whether a hardcover edition makes commercial sense, because it does not scale with length: the longer the book, the smaller the hardcover premium as a proportion.
What Deckle Exports
Deckle produces the interior, which is the same file for both bindings provided the page count and trim size are legal for each. Covers are a separate job in a design tool using the platform's template.
Two things to check when planning a hardcover:
- Trim size. Of Deckle's six sizes, 5.5 by 8.5, 6 by 9 and 6.14 by 9.21 have KDP hardcover support. 5 by 8, BoD 135 by 215 mm and A5 do not, though IngramSpark offers hardcover at 5 by 8 and case laminate at A5.
- Page count. Deckle's estimated page count, shown before export, is what tells you whether you clear the 75-page hardcover floor or the 550-page ceiling. The trim size decision moves that number in both directions.
Deckle's gutter enforcement uses KDP's page-count bands, which as noted above are the same for both bindings, so no hardcover-specific adjustment is applied or needed.
For the platform comparison generally, see IngramSpark vs KDP formatting requirements.
Common Mistakes
- Assuming a short book can be a hardcover. KDP's floor is 75 pages, more than triple the paperback's.
- Assuming a long book can be. The hardcover ceiling is 550 against a paperback's 828.
- Planning a colour hardcover on standard paper. KDP offers premium colour only.
- Expecting a dust jacket from KDP. Case laminate only. IngramSpark does jackets.
- Expecting a custom trim hardcover. Paperback only at KDP.
- Assuming Lulu matches KDP's minimums. Lulu's hardcover floor is lower than its paperback floor.
FAQ
Q: Can I use the same interior PDF for both? A: Yes, if the page count and trim clear both sets of limits. The margin requirements are identical at KDP.
Q: Why can't I make a 60-page hardcover? A: At KDP the floor is 75 pages. IngramSpark allows 18, and Lulu 24.
Q: How much more does a hardcover cost to print? A: At KDP, $4.65 more per unit in fixed cost. The per-page rate is the same.
Q: Can I get a cloth cover or a dust jacket? A: Not from KDP. IngramSpark offers Digital Cloth and jacketed covers.
Q: Do hardcovers need bigger margins? A: KDP publishes one margin table for both. Going above the minimum is still sensible for a bound board book.