Set up your paperback interior once: the page size to give your document, and Amazon’s minimum inside (gutter), outside, top and bottom margins for your page count. Drawn on a facing-page spread so you can see which edge is which. Free, no signup.
The inside margin protects the bound edge, and its minimum depends on how many pages are clamped in the binding — yours sits in Amazon’s 151–300 page band. On a left-hand page the whole arrangement mirrors: the gutter moves to the right.
The values above are the same in every program. The only thing that differs is where the inside/outside pair is hiding — in most of them it appears only after you turn on facing or mirrored pages.
Amazon publishes 5 inside-margin bands. The applicable minimum grows with the effective page count because a thicker book needs more space at the bound edge.
Amazon says it calculates the page count from the uploaded manuscript and rounds an odd total up to an even number if necessary. This tool preserves the count you entered and separately shows the effective KDP count used for eligibility, the margin band and the cover-calculator handoff. It does not edit your manuscript or instruct you to insert a page.
Top, bottom and outside minimums do not vary with page count. They change only when your interior bleeds, and then the page itself grows: bleed exists on the top, bottom and outside edges of an interior page and never on the bound edge, so the page gains one bleed of width and two of height.
Every figure is a KDP MINIMUM. Amazon permits larger margins and allows the outer three margins to differ as long as each meets its minimum; this tool does not recommend a typography measurement. All 16 standard US-store paperback trims are covered; hardcover, custom trims and other marketplaces are outside scope.
Transcribed from Amazon KDP’s published paperback trim size, bleed and margin guidelines, US store (kdp.amazon.com). Last verified 27 August 2026.
No, and confusing the two is the most common interior setup mistake. The spine width is part of the COVER — it is how thick the printed block of paper is, and it is calculated from your page count and paper. The gutter is the inside margin on an interior page: extra white space on the bound edge so your text is not swallowed by the curve of the binding. This calculator gives you the gutter. The spine belongs to the cover calculator.
The inside edge has to allow for the binding, and Amazon increases its minimum as the effective page count grows. The top, bottom and outside minimums come from a separate rule and do not change between page-count bands.
This calculator does not tell you to add one. Enter the final formatted page count your layout program reports. Amazon says it calculates the uploaded manuscript and rounds an odd total up to an even number if necessary. The tool keeps your submitted count unchanged and shows the effective count separately; confirm the processed file in KDP Print Previewer before publishing.
A bleeding page has to extend beyond the finished trim so artwork can be cut back to the edge. KDP adds bleed on the top, bottom and outside edges only, never on the bound edge. The result panel shows the exact engine-derived upload size and extension for your selected trim.
Use bleed when an image, background or illustration is meant to reach a finished page edge. If even one page needs bleed, Amazon says the whole manuscript file should use bleed dimensions, and interior bleed requires a fixed-format file such as a print-ready PDF.
They are Amazon’s published minimums, not a design recommendation. Amazon allows larger margins and does not require the top, bottom and outside values to match. Choose any larger values in your layout program based on your own typography and design requirements.
Recheck the final formatted count here. A change can move the book into another inside-margin band or outside the selected trim and print option’s eligibility window. It also changes the effective page count handed to the cover calculator.