KDP Cover Size Chart: Every Trim Size With Spine Math

Your KDP cover file is not the size of your book. It is the size of your book unfolded, plus a spine that depends on your page count, plus bleed on every cut edge. This chart works the math out for KDP's standard paperback trims so you can see your real file dimensions before you design a single pixel, and it gives you the formula to recalculate for any page count.

The formula (everything below is this, applied)

Spine width = page count × paper factor White paper, black and white interior: 0.0025 in per page. Cream paper: 0.0027 in per page. Color interior: about 0.0028 in per page.

Full cover width = 0.125 + trim width + spine + trim width + 0.125 Full cover height = trim height + 0.25

The 0.125 in additions are bleed: artwork must extend past the trim edge so the cut never exposes white.

Full cover dimensions at 200 pages, white paper (spine 0.50 in)

These are paperback dimensions. Every change in page count moves the width: at 300 pages on white paper the spine is 0.75 in, so add 0.25 in to every width above; at 100 pages the spine is 0.25 in, so subtract 0.25 in. On cream paper the spine grows slightly faster (a 300 page cream book has a 0.81 in spine). Rather than hand calculating variations, enter trim, pages and paper in the cover template generator and it draws the full template with spine, bleed, safe areas and the barcode zone marked.

Hardcover: same trims, different construction

KDP hardcover offers a shorter trim list: 5.5 x 8.5 in, 6 x 9 in, 6.14 x 9.21 in, 7 x 10 in and 8.5 x 11 in. The interior page count produces a similar spine calculation, but the cover file is larger than the paperback math above because the printed case wraps around rigid boards: the file extends beyond the trim on all sides for the wrap, and the spine widens by the boards. Do not reuse paperback dimensions for a hardcover file. Generate the hardcover template for your exact title, which KDP provides during setup, and build to it. Our spine width guide explains the construction differences in detail.

Reading the chart like a designer

Trim choice is a business decision. Bigger trims mean fewer pages for the same words, which lowers the print cost per copy, which is margin on every sale forever. It also changes the shelf feel: 5 x 8 in reads mass market, 6 x 9 in reads standard trade, 8.5 x 11 in is workbook territory. Pick with the royalty calculator open, not by vibes. (How trim interacts with interior setup is covered in our KDP formatting guide.)

Page count is a design output, not an input. The chart takes page count as given, but page count comes from your formatted interior: font, size, leading and trim decide it. Lock the interior first, read the final count, then calculate the cover. Designing a cover to a guessed page count is the most common cause of spine rejections we rescue.

Keep the critical content inside the lines. Titles, author names and logos live in the safe area, away from trim and folds. The barcode owns the lower back cover. The chart gives you the canvas; the template shows you the zones, and the zones are where covers pass or fail inspection.

FAQ

What size is a KDP ebook cover? Ebooks have no spine or bleed: a single front cover image, 2560 x 1600 px recommended, at a 1.6:1 ratio.

What if my trim size is not listed? KDP accepts a defined list per binding. If your size is not on it, the book cannot be produced at that size on KDP; choose the nearest listed trim and reformat the interior to it.

Does the chart apply to IngramSpark? No. IngramSpark runs its own trim list and spine tables. The method (page count times paper factor, plus bleed) is the same, the numbers are theirs.

Why was my cover rejected when I used these dimensions? Usually because the page count used for the spine was not the final count, or the file was exported at trim size without bleed. Recheck both against your title's own generated template before upload.