Book Cover Size & Spine Width Calculator
Enter the trim size, page count and paper to get the spine width and the full cover size with bleed. Works for Amazon KDP paperbacks and print-shop covers. Free, no sign-up.
KDP 24–828 pages
Starts with a free account. You get a cover layout with this trim size, spine and bleed already set up (and the barcode area for KDP).
How it is calculated
For KDP, spine width = page count × the thickness of one page (an odd page count is rounded up with one blank page). The cover is 0.125 in bleed + back cover + spine + front cover + 0.125 in bleed wide, and the trim height plus top and bottom bleed tall. Page thickness and page limits (for 6 × 9 in):
| Ink · Paper | Per page | Page limits |
|---|---|---|
| Black & white · White paper | 0.002252 in | 24–828 |
| Black & white · Cream paper | 0.002500 in | 24–776 |
| Standard color · White paper | 0.002252 in | 72–600 |
| Premium color · White paper | 0.002347 in | 24–828 |
For a print-shop cover the spine is the number of sheets (pages ÷ 2, rounded up) × the thickness of one sheet. Papers of the same weight differ in thickness, so confirm the spine width with your printer before printing. Flaps add twice the flap width to the cover.
KDP does not allow spine text on books under 79 pages. Before uploading, compare once with KDP's own cover template.
Frequently asked questions
How is the spine width of a KDP cover calculated?
Multiply the page count by the thickness of one page: 0.002252 in for black-and-white on white paper, 0.0025 in on cream paper and 0.002347 in for premium color. A 200-page book on white paper has a 0.4504 in (11.4 mm) spine.
Does the full cover size include bleed?
Yes. A KDP cover adds 0.125 in (3.2 mm) of bleed on all four edges, so a 6 × 9 in, 200-page book on white paper needs a cover of about 12.70 × 9.25 in.
What pixel size should I use in Canva or Photoshop?
Print covers are made at 300 dpi, so use the '300 dpi pixels' value as your canvas size. For a 6 × 9 in, 200-page book on white paper that is 3810 × 2775 px.
How are print-shop covers different?
The spine is measured from the paper caliper, covers often have flaps, and bleed is usually 3 mm. There is no fixed barcode position. Specifications vary between printers, so confirm the final numbers with yours.
Can I design the cover at this size right away?
Click 'Create a cover at this size' and PodoLay creates a cover layout at that size, with the back cover, spine and front cover, the bleed and the KDP barcode area set up. If the page count changes later, the spine can be re-measured. It runs in the browser and starts free.