KDP margin calculator
Trim size, page count and whether you use bleed — those three decide every margin on a KDP paperback page. Enter them and get the numbers to type into your document, plus which side the gutter goes on. Custom sizes work too, anything KDP accepts: 4" to 8.5" wide, 6" to 11.69" tall.
KDP takes widths from 4" to 8.5" and heights from 6" to 11.69".
Opens the generator with this exact book already set up. Nothing to re-type.
Two facing pages, to scale. Shaded = where content may go. The gutter is the margin against the spine, and it swaps sides.
Your page at 300 DPI, —, with the margins, the gutter side and the bleed drawn on it. Put it under your page as the bottom layer, then hide it before you export.
The gutter table
KDP's inside margin depends on the total page count, because a thicker book swallows more of the page in the binding. The ranges below are worded as they are on KDP's trim, bleed and margins page, checked 22 October 2026:
| Page count | Inside (gutter) | Outside, top, bottom |
|---|---|---|
| 24 to 150 pages | 0.375" (9.6 mm) | 0.25" (6.4 mm), or 0.375" (9.6 mm) with bleed |
| 151 to 300 pages | 0.5" (12.7 mm) | |
| 301 to 500 pages | 0.625" (15.9 mm) | |
| 501 to 700 pages | 0.75" (19.1 mm) | |
| 701 to 828 pages | 0.875" (22.3 mm) |
These are minimums: KDP rejects less and accepts more. KDP's previewer can still report "insufficient gutter" for a file that sits exactly on them: Vellum's help page on that error says it "can even happen with a value that matches KDP's minimum". Puzzle Press uses these figures for the book's page count and keeps every mark a further 1/32" (0.031") inside them.
Page size with bleed, for every trim
Bleed is for artwork that runs off the edge of the page. KDP trims 0.125" from the top, bottom and outside edge, so with bleed on, the PDF page is 0.125" wider and 0.25" taller than the trim. It is not wider by 0.25": the inside edge goes into the binding and is never trimmed.
That is worth checking, because some bleed calculators for KDP interiors give a 6 × 9 book a page of 6.25 × 9.25 (1875 pixels wide). That applies the cover's four-sided bleed to an interior, and makes every page 0.125" wider than KDP expects. KDP's own trim and bleed page gives 6.125 × 9.25 for the same book.
| Trim | PDF page with bleed | In millimetres | Pixels at 300 DPI |
|---|---|---|---|
| 5" × 8" | 5.125" × 8.25" | 130.2 × 209.5 mm | 1538 × 2475 |
| 5.5" × 8.5" | 5.625" × 8.75" | 142.9 × 222.3 mm | 1688 × 2625 |
| 6" × 9" | 6.125" × 9.25" | 155.6 × 234.9 mm | 1838 × 2775 |
| 7" × 10" | 7.125" × 10.25" | 181.0 × 260.3 mm | 2138 × 3075 |
| 8" × 10" | 8.125" × 10.25" | 206.4 × 260.3 mm | 2438 × 3075 |
| 8.5" × 11" | 8.625" × 11.25" | 219.1 × 285.8 mm | 2588 × 3375 |
Pixel sizes are rounded up. Anything that should bleed must reach the page edge, and anything that must not be cut off stays inside the outside margin. With bleed, that is 0.5" from the PDF page edge (0.375" plus the 0.125" that is trimmed away), and the calculator above measures it the same way. The cover bleeds 0.125" on every side as well, and its width also depends on the spine. The spine calculator gives the full cover size.
Setting it up in Word, Google Docs or InDesign
Set the page size to the trim (or the trim plus bleed, if you use it). Turn on mirror margins (Word: Layout → Margins → Custom → Multiple pages: Mirror margins; InDesign: Facing pages). Then "inside" is the gutter figure above and "outside" is the outer figure. Export to PDF with fonts embedded — an un-embedded font is the other common rejection, and the previewer's message about it is not obvious.
In Canva or Affinity: a page template
Designing page by page, the gutter is easy to put on the wrong side. Set your trim, page count and bleed above, then download the odd-page and the even-page template. Each is a PNG at 300 DPI, exactly the size of the PDF page KDP expects, with KDP's minimum margins drawn as a blue dashed box and the gutter shaded on the side it belongs: the left of odd pages, the right of even ones. With bleed on, the extra 0.125" is drawn in pink on the outside edge, the top and the bottom only. Put the matching template under each page as the bottom layer, keep text inside the blue box, and hide the layer before you export.
Then the cover, and the price
The page count you used here also fixes the spine width and the cover size — the spine calculator does that sum — and the printing cost, which the royalty calculator turns into what you keep per copy. All three use Amazon's published figures. If you are new to this, the guide walks the whole thing in order.
Making a puzzle book?
Puzzle Press lays out the whole paperback — word search, sudoku, mazes, fill-ins or crosswords with solutions — inside these margins, gutter side included, then the cover with the spine worked out from the page count. Free to use; pay only to remove the PREVIEW cover mark.
Make a book freeSee a finished book (PDF) · and its cover — made with it, nothing mocked up.
No sign-up. $19 once removes the PREVIEW cover mark; 30-day refund, no questions.
Making a handwriting workbook instead? Trace Press, from the same maker, lays out an A–Z letter tracing book and its cover to the same KDP rules. For a practice notebook, its free handwriting paper is already inside KDP's margins at every trim.