KDP rejects covers when the file dimensions don’t match the calculated size for your trim, page count, and paper type. The cover must include the front panel, spine, back panel, and 0.125” bleed on all edges — and the dimensions must be exact to within 0.01”. The most common mistake: calculating cover size before finalizing your interior, then changing the page count (which changes spine width, which changes total cover width). Even a 10-page change can alter the cover by 0.025” — enough for KDP to reject it.
Cover dimension formula
Total width = bleed + back panel + spine + front panel + bleed = 0.125” + trim width + spine width + trim width + 0.125”
Total height = bleed + trim height + bleed = 0.125” + trim height + 0.125”
Spine width
Cream paper: page count × 0.0025” White paper: page count × 0.002252”
Quick reference for common trims
| Trim | Pages | Paper | Spine | Cover Width | Cover Height | Pixels (300 DPI) |
|---|---|---|---|---|---|---|
| 5.5×8.5 | 250 | Cream | 0.625” | 11.875” | 8.75” | 3,563 × 2,625 |
| 5.5×8.5 | 300 | Cream | 0.750” | 12.000” | 8.75” | 3,600 × 2,625 |
| 6×9 | 250 | Cream | 0.625” | 12.875” | 9.25” | 3,863 × 2,775 |
| 6×9 | 300 | White | 0.676” | 12.926” | 9.25” | 3,878 × 2,775 |
| 5×8 | 300 | Cream | 0.750” | 11.000” | 8.25” | 3,300 × 2,475 |
For your exact dimensions, use the Cover Size Calculator.
Common mistakes
1. Page count changed after cover was made
You finalized your interior at 280 pages, sent dimensions to your cover designer, then added back matter that pushed it to 295 pages. The spine changed from 0.700” to 0.738” — your cover is now 0.038” too narrow.
Fix: Always finalize your interior page count BEFORE creating the final cover. If the interior changes, recalculate and update the cover.
2. Using trim size instead of cover size
Your cover file is 5.5” × 8.5” (the trim size). It needs to be ~12” × 8.75” (the full cover including spine and bleed).
Fix: The cover wraps around the entire book — front, spine, and back, plus bleed.
3. Wrong paper type in calculation
Cream and white paper have different spine formulas. A 300-page book on cream = 0.750” spine, on white = 0.676” spine. Using the wrong paper type makes your cover 0.074” off.
Fix: Match the paper type in your spine calculation to what you selected in KDP.
4. Missing bleed
KDP requires 0.125” bleed on all four edges of the cover. If your cover file is the exact wrap-around size without bleed, it’s too small by 0.25” in each dimension.
Fix: Add 0.125” bleed to all edges.
Cambric calculates exact cover dimensions from your interior page count. Send the numbers and a visual template to your cover designer — no manual math.
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Cover file specifications
| Requirement | Value |
|---|---|
| Format | PDF or JPEG |
| Resolution | 300 DPI minimum |
| Color space | RGB (KDP converts for print) |
| Bleed | 0.125” on all four edges |
| Barcode area | Leave 2” × 1.2” in lower-right of back panel for KDP’s barcode (or place your own) |
Using KDP’s cover template
KDP provides a free cover template calculator:
- Go to KDP’s cover calculator
- Enter your trim, page count, and paper type
- Download the PNG template with guidelines
- Send it to your cover designer
Or use our Cover Size Calculator for instant dimensions without navigating KDP’s dashboard.
Related guides
- Cover Size Calculator — instant dimensions
- Spine Width Calculator — spine for your page count
- KDP file rejection fixes — all common errors
- KDP Book Calculator — page count + spine + cost