Free KDP cover calculator
Cover design guide
Book cover spine size: page count and paper decide it.
Spine width is calculated, not guessed. Get the number right and the wrap fits the book block.
Checked:
✓Page count times paper factor✓Add 0.125-inch bleed all around✓One continuous wrap PDF
Paperback cover dimensions
Spine width0.450 in11.44 mm
Full cover size12.700 × 9.250 in322.59 × 234.95 mm
Canvas (300 DPI · Canva)3810 × 2775 px300 DPI · Canva custom size
Spine text
Eligible: more than 79 pages. Keep at least 0.0625 in from each spine edge.
Reference chart: every KDP trim at 100, 200, and 300 pages
Paper: Black & white · white paper
| Trim size | Pages | Spine | Full wrap (in) | 300 DPI canvas (px) |
|---|---|---|---|---|
| 5" × 8" | 100 | 0.225 in | 10.475 × 8.250 in | 3143 × 2475 px |
| 5" × 8" | 200 | 0.450 in | 10.700 × 8.250 in | 3210 × 2475 px |
| 5" × 8" | 300 | 0.676 in | 10.926 × 8.250 in | 3278 × 2475 px |
| 5.25" × 8" | 100 | 0.225 in | 10.975 × 8.250 in | 3293 × 2475 px |
| 5.25" × 8" | 200 | 0.450 in | 11.200 × 8.250 in | 3360 × 2475 px |
| 5.25" × 8" | 300 | 0.676 in | 11.426 × 8.250 in | 3428 × 2475 px |
| 5.5" × 8.5" | 100 | 0.225 in | 11.475 × 8.750 in | 3443 × 2625 px |
| 5.5" × 8.5" | 200 | 0.450 in | 11.700 × 8.750 in | 3510 × 2625 px |
| 5.5" × 8.5" | 300 | 0.676 in | 11.926 × 8.750 in | 3578 × 2625 px |
| 6" × 9" | 100 | 0.225 in | 12.475 × 9.250 in | 3743 × 2775 px |
| 6" × 9" | 200 | 0.450 in | 12.700 × 9.250 in | 3810 × 2775 px |
| 6" × 9" | 300 | 0.676 in | 12.926 × 9.250 in | 3878 × 2775 px |
| 6.14" × 9.21" | 100 | 0.225 in | 12.755 × 9.460 in | 3827 × 2838 px |
| 6.14" × 9.21" | 200 | 0.450 in | 12.980 × 9.460 in | 3894 × 2838 px |
| 6.14" × 9.21" | 300 | 0.676 in | 13.206 × 9.460 in | 3962 × 2838 px |
| 7" × 10" | 100 | 0.225 in | 14.475 × 10.250 in | 4343 × 3075 px |
| 7" × 10" | 200 | 0.450 in | 14.700 × 10.250 in | 4410 × 3075 px |
| 7" × 10" | 300 | 0.676 in | 14.926 × 10.250 in | 4478 × 3075 px |
| 8" × 10" | 100 | 0.225 in | 16.475 × 10.250 in | 4943 × 3075 px |
| 8" × 10" | 200 | 0.450 in | 16.700 × 10.250 in | 5010 × 3075 px |
| 8" × 10" | 300 | 0.676 in | 16.926 × 10.250 in | 5078 × 3075 px |
| 8.5" × 11" | 100 | 0.225 in | 17.475 × 11.250 in | 5243 × 3375 px |
| 8.5" × 11" | 200 | 0.450 in | 17.700 × 11.250 in | 5310 × 3375 px |
| 8.5" × 11" | 300 | 0.676 in | 17.926 × 11.250 in | 5378 × 3375 px |
| 8.5" × 8.5" | 100 | 0.225 in | 17.475 × 8.750 in | 5243 × 2625 px |
| 8.5" × 8.5" | 200 | 0.450 in | 17.700 × 8.750 in | 5310 × 2625 px |
| 8.5" × 8.5" | 300 | 0.676 in | 17.926 × 8.750 in | 5378 × 2625 px |
Paperback calculation uses KDP's published 0.125 in bleed and current paper thickness factors. Always confirm the final page count after interior formatting.
The formula behind the spine
KDP computes the spine as final page count times a paper factor: 0.002252 for white, 0.0025 for cream, 0.002347 for premium color.
- Use the final page count, never the draft
- Recalculate after every layout change
- No spine text below 80 pages
Generating the full wrap
Enter page count, trim size, and paper into the cover calculator. It returns the full wrap with bleed and an SVG guide for your design file.
FAQ
Frequently asked questions
How do I know my final page count?
Format the interior first. The formatted PDF's page count is the number the spine formula uses.
What happens if the spine is 1mm off?
The cover shifts against the block. KDP rejects files where the spine width does not match the computed value.
Do all paperbacks need spine text?
No — but if you add it, it must be placed correctly. KDP recommends spine text only on books with enough width (usually 79+ pages), and it must be centered between trim lines and never touch the fold. Books that are too thin should use a clean spine with no text, which is a common professional choice.
Was this publishing guide or tool helpful?
Get the exact wrap dimensions.
Calculate the full cover with spine and bleed in seconds, free.