5.06" × 7.81" cover size for a 50-page book
Spine width, full-wrap dimensions, and print-ready pixel sizes for a 50-page 5.06" × 7.81" KDP paperback on white paper with a black-ink interior.
- Spine width
- 0.113"
- Full cover (no bleed)
- 10.233" × 7.810"
- Full cover (with bleed)
- 10.483" × 8.060"
- At 300 DPI
- 3,145 px × 2,418 px
Change the paper, ink, or page count
The calculator below starts on this book's settings. Switching to cream paper or a colour interior changes the spine width, because the paper is a different thickness.
Your cover dimensions
| Measurement | Inches | Centimeters | Pixels @300dpi | Points |
|---|---|---|---|---|
| Full cover width (with bleed) | 10.483 | 26.63 | 3145 | 754.8 |
| Full cover height (with bleed) | 8.060 | 20.47 | 2418 | 580.3 |
| Spine width | 0.113 | 0.29 | 34 | 8.1 |
Cover bleed is a flat 0.125in on every non-spine edge, per KDP's published spec (verified 22 July 2026). KDP prints spine text only on books with more than 79 pages (verified 31 July 2026); allow around 150 for type that stays comfortably legible after its required 0.0625in of clearance on each side.
Cover guide
How this spine width is worked out
A paperback spine is the stacked thickness of its pages, so the width is the page count multiplied by a per-page paper thickness. At 50 pages on white stock that comes to 0.113".
The full-wrap cover is two 5.060" covers plus that spine, which is why the no-bleed width is 10.233". KDP's standard 0.125" bleed then adds a quarter inch to both dimensions, giving the file size you actually upload.
What this book costs to print
On Amazon.com, a 50-page 5.06" × 7.81" paperback with a black-ink interior costs $2.30 per copy to print — this trim is in KDP's standard band. That sets a price floor of $4.60: below it, a sale would earn a negative royalty and KDP will not accept the price.
At 50 pages this book is inside KDP's flat-fee band. Every black-ink paperback from 24 to 110 pages costs the same $2.30 to print on Amazon.com, whatever its length — so the next 60 pages cost you nothing per copy. Trimming the interior to save money does not work here; you are already at the floor.
A 50-page 5.06" × 7.81" has no printable spine
The spine measures 0.113", and KDP will print nothing on it: spine text needs more than 79 pages and this book is 30 short. Leave the spine artwork blank — a title set there is a rejection at upload, not something KDP drops quietly for you.
5.06" × 7.81" is a 1:1.54 page — the classic book proportion, which is what most cover templates assume. The full wrap at 50 pages is 10.483" × 8.060" with bleed, of which the spine takes 1.1% of the width. KDP's barcode block is a fixed 2in × 1.2in whatever the trim, so on this size it claims 6% of the back cover — keep anything that needs reading out of it. KDP offers 5.06" × 7.81" in paperback only.
Worth knowing before you commit to the size: the same 50-page book at 6" × 9" costs exactly the same $2.30 to print. KDP prices paperbacks by trim CATEGORY and page count, not by area, and both of these are in its standard-size band — so at this length 5.06" × 7.81" against 6" × 9" is a design decision, not a margin one.
What 5.06" × 7.81" is for: Matching the classic mass-market paperback footprint — genre fiction aiming to sit alongside traditionally published paperbacks, and series where shelf consistency with existing mass-market titles matters.
SmartKDP is not affiliated with, endorsed by, or sponsored by Amazon. Amazon, Kindle, and Kindle Direct Publishing are trademarks of Amazon.com, Inc. or its affiliates.
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