What Size Is Amazon KDP? (Paperback Trim Sizes)
If you are asking what size Amazon KDP is, the answer is: you choose from Amazon’s supported trim sizes when you set up your paperback. Your interior PDF must match that exact trim — not “close enough.”
Common fiction trims include roughly 5 × 8 in and 5.25 × 8 in; nonfiction often lands near 5.5 × 8.5 in or 6 × 9 in trade sizes — but the authoritative list is always Amazon’s own calculator and help pages for your edition type.
Once you pick a trim, every export from your design tool must match it. If the PDF is even slightly off, KDP’s checker may reject the upload or you may get a proof with shifted margins.
InkAlign hosts dedicated interior fixers by trim so you can process your PDF against the same standard sizes you will select in KDP — with a free scan first, then a print-ready download when you are satisfied. That keeps “which size is KDP?” aligned with “which size is my book.”
Pick your trim in InkAlign, then upload your PDF
Go to InkAlign