KDP Cover Calculator
Work out the spine width and the full wrap-around cover size for an Amazon KDP paperback. Pick a trim size, a paper type and a page count — the numbers update as you type. No signup.
0.002 in per page
KDP allows 24–828 pages on this paper.
KDP only prints spine text above 79 pages. At 60 pages the spine stays blank.
Our cover wizard builds a print-ready PDF at exactly these dimensions — and can read the true size straight out of an official KDP template file.
How the math works
A paperback cover is one flat image containing the back, the spine and the front. Two numbers decide its size.
Spine width = page count × the per-page thickness of the paper you chose. This is the number that moves: change the page count or switch paper and the spine changes with it.
Full cover width = back panel + spine + front panel + 0.125 in of bleed on each outer edge, so (2 × trim width) + spine + 0.25 in.
Full cover height = trim height + 0.125 in top + 0.125 in bottom.
Upload at 300 DPI. Multiply the inch dimensions by 300 for the pixel size your file needs to be.
Paper thickness and page limits
KDP's per-page caliper by interior type, with the maximum page count each one supports.
| Interior & paper | Per page | Max pages |
|---|---|---|
| Black & white interior, white paper | 0.002252 in | 828 |
| Black & white interior, cream paper | 0.0025 in | 776 |
| Standard colour interior | 0.002252 in | 800 |
| Premium colour interior | 0.002347 in | 600 |
Minimum 24 pages on every paper type. Spine text is printed only above 79 pages.
Frequently asked questions
How do I calculate the spine width for a KDP paperback?
Multiply the page count by the per-page thickness of your paper. KDP uses 0.002252 in per page for white paper, 0.0025 in for cream, 0.002347 in for premium colour and 0.002252 in for standard colour. A 120-page white-paper book has a spine of 120 x 0.002252 = 0.27024 in.
What size should my full KDP cover file be?
The wrap-around file covers the back, the spine and the front in one image. Width = (2 x trim width) + spine width + 0.25 in of bleed. Height = trim height + 0.25 in of bleed. KDP expects 300 DPI, so multiply both by 300 to get pixels.
How much bleed does KDP require on a cover?
0.125 in on the top, bottom and the two outer edges. There is no bleed between panels, because the spine sits inside the same image.
When does KDP print text on the spine?
Only above 79 pages. Below that the spine is too narrow to print on reliably, so KDP leaves it blank even if your artwork contains text there.
What is the maximum page count for a KDP paperback?
It depends on the paper: 828 pages on white, 776 on cream, 800 on standard colour and 600 on premium colour. The minimum is 24 pages on every paper type.
Why does my cover keep getting rejected by KDP?
Almost always because the file no longer matches the book. Changing the page count or the paper type changes the spine, which changes the whole wrap width — so a cover that passed yesterday fails today. Recalculate whenever either one changes.
Now make the cover
Knowing the size is the easy half. Our AI book cover generator generates the artwork and exports a print-ready wrap PDF at exactly these dimensions — and it can read the true size directly out of an official KDP template file, so you never hand-enter it. Making a colouring book? The coloring book maker keeps one character consistent across every interior page and then carries that same character onto the cover.