Free KDP cover calculator
Free cover file check
Check DPI and bleed before uploading the cover.
Choose a PNG or JPG and the KDP cover file check reports width, height, estimated print DPI, and whether the outside edges carry enough bleed.
Checked:
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A 300-page 6 x 9 paperback, in full-wrap numbers
The spine is the number authors get wrong, and it is not a guess: page count multiplied by the paper factor. White paper is 0.002252 in per page, cream is 0.0025, and premium colour is 0.002347, so 300 white pages produce a 0.676 in spine. Add both covers, the spine, and the 0.25 in of bleed and the file must be 12.926 x 9.25 in — 3878 x 2775 px at 300 DPI, exported as one single-page PDF.
Check the image you already have against that width before anything else. A front cover exported at 1800 x 2700 px is a front cover, not a wrap, and KDP rejects it for dimensions rather than for quality. Background art has to cross the trim line by 0.125 in on the top, bottom, and outside edges, or a small trimming drift leaves a white sliver along the edge of the finished book.
- Page counts below 24 are raised to 24, because KDP will not print a thinner paperback
- The barcode keeps a 2 x 1.2 in zone in the back-cover panel, so keep the blurb out of it
- Spine copy needs a thick spine: the calculator only enables it from 80 pages
| Trim | Pages | Paper | Spine | Full wrap | 300 DPI pixels |
|---|---|---|---|---|---|
| 6 x 9 in | 300 | White | 0.676 in | 12.926 x 9.25 in | 3878 x 2775 px |
| 6 x 9 in | 300 | Cream | 0.750 in | 13.000 x 9.25 in | 3900 x 2775 px |
| 6 x 9 in | 120 | White | 0.270 in | 12.520 x 9.25 in | 3756 x 2775 px |
| 8.5 x 8.5 in | 100 | White | 0.225 in | 17.475 x 8.75 in | 5243 x 2625 px |
| 8.5 x 11 in | 100 | White | 0.225 in | 17.475 x 11.25 in | 5243 x 3375 px |
The three number checks that decide acceptance
KDP accepts covers only when the file matches the required geometry: correct pixel dimensions for the trim and page count, a 300-DPI-equivalent density, and a 0.125-inch bleed on top, bottom, and outside edges. Each mismatch produces a different error at upload, and fixing one often exposes the next.
The checker reads the image's pixel dimensions and your chosen print size, then reports the effective print DPI and whether the outside edges carry enough margin for the bleed. It is a preparer's check, not a substitute for KDP's preview: you still approve the on-screen book preview before publishing.
- A full-wrap PDF is exported as one file — back, spine, front
- Backgrounds that touch the edge must extend into the bleed
- If you are not sure of the trim, run the cover calculator first
What the checker cannot measure
It does not read color profiles, embedded fonts, or heavy line weights, and it cannot tell whether your spine text sits inside the interlocking security zone. Those checks are the reason KDP shows its own preview, which is also where authors catch blurry artwork and cut-off titles — a physical proof is the final guard before ordering author copies.
FAQ
Frequently asked questions
Why was my cover file rejected for its size?
Almost always the wrap width. The file must be twice the trim width plus the spine plus 0.25 in of bleed, and the spine is page count multiplied by the paper factor — 0.002252 in per white page. A 300-page 6 x 9 paperback needs 12.926 x 9.25 in, which is 3878 x 2775 px at 300 DPI.
Can I resize a front cover into a full wrap?
No. A wrap file contains the back cover, spine, and front cover at their true relative widths, so a front-cover-sized image cannot be stretched into it without distorting the artwork. Export the whole wrap from your layout at the calculated pixel dimensions instead.
How much bleed does a KDP cover need?
0.125 in on the top, bottom, and outside edges, which adds 0.25 in to both the wrap width and the wrap height. Background art that reaches the trim edge has to extend into that bleed, otherwise a small trimming drift leaves a white sliver on the finished book.
Does the checker see colour profile or fonts?
No. It reads pixel dimensions, the implied print DPI, and whether the outside edges carry enough margin for bleed. Colour conversion, embedded fonts, and spine text placement only appear in KDP's own on-screen preview, so approve that preview before publishing.
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Fix the file before KDP sees it.
Run the full cover geometry in the calculator after the image check.