An illustration with sample files; your own files show their own results.
Before3 designs that would print badly
Blurry, too few pixels
White box around it
Outside the safe zone
AfterThe same designs, print-ready
Sharp at 300 DPI
Transparent PNG, no box
Inside the safe zone
KDP Paperback Cover Checker: 6 × 9 in Full-Wrap Pre-Flight
A KDP paperback cover is one flat image: back cover, spine and front cover side by side, with bleed all round. Its width depends on the page count and paper, so a cover sized for the wrong number of pages is rejected or prints with the spine in the wrong place.
This preset is a 6 × 9 inch paperback wrap at 300 DPI with 0.125 inch bleed, on a 3900 × 2775 pixel canvas with the spine sized for roughly 150 pages. The checker measures your file against it, checks bleed and safe margins, and exports print-ready output. For another page count, choose Custom canvas and enter the exact dimensions from KDP's cover template.
POD Design Checker: DPI, Bleed and Size Check for Print-on-Demand
A print pre-flight tool for print-on-demand designers. Drop in up to 50 designs and it checks each one against a platform's real specs (Merch by Amazon, Printify, Printful, posters, mugs, phone cases, KDP covers) for resolution, safe margins, bleed, transparency and CMYK gamut, then exports print-ready files. Every pixel stays on your machine.
What it measures
Resolution is read from your file's real pixel size divided by the product's physical print size, giving the effective DPI along the limiting axis: the number the printer sees. Safe-margin checks trace your artwork's actual content and test whether it clears the safe zone. Transparency scans the alpha channel for a solid background and for the soft-edge “halo” that dirties a cut-out.
Runs in your browser
Decoding, alpha scanning, background removal, DPI compositing and DPI stamping run locally, with the heavy pixel work in a Web Worker so the batch stays responsive. Your artwork is never uploaded, which matters when designs are your inventory. Exports are built and zipped in the browser too.
Frequently asked questions
How wide is a KDP paperback cover?
A KDP paperback cover is the back cover, the spine and the front cover added together, plus bleed, so its width changes with the trim size, the page count and the paper. This preset's canvas is 3900 × 2775 pixels, which is 13 × 9.25 inches at 300 DPI, with a spine sized for roughly 150 pages. For any other page count, use KDP's cover template and enter its exact dimensions as a Custom canvas.
What is bleed, and why does a cover need it?
Bleed is artwork that extends past the trim line so that a small cutting shift does not leave a white edge. This preset uses 0.125 inch of bleed, and the validator checks that important content stays inside the safe margin while the artwork runs out to the edge.
What resolution does a KDP cover need?
300 DPI at the final printed size is the usual requirement. The check compares your pixel dimensions with the physical size, so an image that looks sharp on screen can still fall short; the report shows the DPI it works out.
Is my cover uploaded anywhere to be checked?
No. The whole check runs in your browser and the file is never uploaded. Previewing and checking need no account; an account is needed only to spend tokens when you download the result.
