KDP Paperback Margins and Gutter by Page Count
KDP’s current minimum inside/gutter margin increases as page count rises, while top/bottom/outside minimums are 0.25 in without bleed and 0.375 in with bleed. These are minimums, not a guarantee that a dense layout is comfortable to read.
Use the numbers from your actual job
The guide explains the decision; the linked calculator gives you the value for your own file or production assumptions.
The inside margin grows with book thickness
KDP currently specifies 0.375 in for 24–150 pages, 0.5 in for 151–300, 0.625 in for 301–500, 0.75 in for 501–700 and 0.875 in for 701–828 pages. The binding side therefore changes when the final page count crosses a band.
Bleed changes the outside minimum
For no-bleed interiors, KDP’s minimum top, bottom and outside margins are 0.25 in. For bleed interiors, the stated minimum is 0.375 in. The inside/gutter rule is still governed by page count.
Set page geometry before fine layout
Choose trim size, bleed mode and final page count before locking typography. A change to any of these can alter the page size or usable content area and force reflow.
Minimum does not mean ideal
Provider acceptance limits are not typography recommendations. Complex headers, footers, large books or visually dense pages may benefit from more white space than the minimum required for manufacturing.
Practical answer
KDP’s current minimum inside/gutter margin increases as page count rises, while top/bottom/outside minimums are 0.25 in without bleed and 0.375 in with bleed. These are minimums, not a guarantee that a dense layout is comfortable to read.
When the decision affects a paid print run, book upload, client order or expensive material, keep the calculation with the job notes and verify any external specification again immediately before production.