Book Spine Width Calculator
Work out your paperback's spine width for Amazon KDP or IngramSpark in seconds. You also get your full cover size and a printable template.
The spine width formula
Spine width = number of pages × thickness of one page. The thickness depends on the paper your printer uses, so the same book has a slightly different spine at each printer.
Amazon KDP (from KDP's own help pages)
| Paper | Per page |
|---|---|
| White (black & white) and standard color | 0.002252" |
| Cream (black & white) | 0.0025" |
| Premium color | 0.002347" |
IngramSpark (estimate from IngramSpark's paper specifications)
| Paper | Pages per inch |
|---|---|
| White 50# | 512 |
| Creme 50# | 444 |
| Groundwood 38# | 400 |
| Color / Premium color 70# | 377 |
IngramSpark sends you an exact cover template for your book through its free cover template generator. Use it for your final file; the IngramSpark result here is an estimate for planning.
Three spine mistakes that get books rejected
- Using another printer's numbers. A KDP spine is not an IngramSpark spine. Build one cover per printer.
- Changing paper after the cover is done. Switching white to cream on KDP makes a 300-page spine about 0.07" wider, enough to wrap your spine art onto the front.
- Spine text on a thin book. KDP prints spine text only on books with more than 79 pages; IngramSpark not below 48 pages.
Let SparkPrep check the whole cover for you
SparkPrep measures your real cover file: spine width, spine text, bleed, safe margins, barcode area and template leftovers. It tells you what's wrong in plain English and fixes it before you upload.
Check my cover with SparkPrep KDP cover calculatorMore free tools
- KDP cover size calculator & template generator
- Book cover dimensions for every common book size
- IngramSpark cover template guide
- IngramSpark rejection messages explained
SparkPrep is an independent tool and is not affiliated with Amazon or IngramSpark.