KDP Spine Width Calculator
KDP spine width is page count × paper thickness: 0.002252 in per page for white paper or standard color, 0.0025 in for cream paper, and 0.002347 in for premium color. Enter your page count to get the paperback spine in inches, millimeters, and 300 DPI pixels.
Last updated: . Factors from KDP’s paperback cover guide.
- Spine width
- 0.450 in
- In millimeters
- 11.43 mm
- At 300 DPI
- 135 px
- Spine text
- Allowed, up to 0.325 in tall
A full paperback cover also needs 0.125 in of bleed on the top, bottom, and outside edges.
Get the full cover sizeKDP spine width factors by paper
| Interior and paper | Per page | 300 pages |
|---|---|---|
| Black & white, white paper | 0.002252 in | 0.676 in |
| Black & white, cream paper | 0.0025 in | 0.750 in |
| Standard color | 0.002252 in | 0.676 in |
| Premium color | 0.002347 in | 0.704 in |
KDP spine width by page count
| Pages | White or standard color | Cream | Premium color |
|---|---|---|---|
| 100 | 0.225 in | 0.250 in | 0.235 in |
| 150 | 0.338 in | 0.375 in | 0.352 in |
| 200 | 0.450 in | 0.500 in | 0.469 in |
| 250 | 0.563 in | 0.625 in | 0.587 in |
| 300 | 0.676 in | 0.750 in | 0.704 in |
| 400 | 0.901 in | 1.000 in | 0.939 in |
| 500 | 1.126 in | 1.250 in | 1.173 in |
Spine width changes whenever your final page count or paper changes, so recalculate before you export the cover. To turn the spine into a full wrap, use the KDP cover size calculator.
How to use the KDP spine width calculator
- Enter your page count. Use the final page count from your formatted interior PDF, including any blank pages.
- Choose your interior and paper. Pick black and white on white or cream paper, standard color, or premium color.
- Copy the spine width. Use the result in inches, millimeters, or 300 DPI pixels when you set up the cover.
KDP spine width FAQ
What is the KDP spine width formula?
KDP spine width is page count multiplied by the paper factor: 0.002252 in per page for white paper and standard color, 0.0025 in for cream paper, and 0.002347 in for premium color.
How wide is the spine of a 200-page KDP paperback?
A 200-page KDP paperback has a 0.450 in spine on white paper or standard color, 0.500 in on cream paper, and 0.469 in on premium color.
How many pages do you need for spine text on KDP?
KDP requires at least 79 pages for spine text on a paperback you design yourself. Its Cover Creator tool needs 80 pages.
Does trim size change KDP spine width?
No. The spine depends only on page count and paper. Trim size changes the full cover width and height, so use the KDP cover size calculator for those numbers.
How much space should I leave around spine text?
KDP asks for at least 0.0625 in between the text and each spine edge, because every book varies slightly when bound.
Does this calculator work for hardcover books?
No. This page uses the KDP paperback formula. Hardcover covers add hinge and wrap areas, so use the KDP cover size calculator and select hardcover.