KDP Margin and Bleed Calculator

Get the exact PDF page size and the minimum margins KDP accepts for your paperback interior, based on trim size, page count and whether you use bleed.

KDP's margin rules

Page count	Inside (gutter) minimum
24 to 150	0.375" (9.5 mm)
151 to 300	0.5" (12.7 mm)
301 to 500	0.625" (15.9 mm)
501 to 700	0.75" (19.0 mm)
701 to 828	0.875" (22.2 mm)

Outside, top and bottom margins must be at least 0.25" (6.4 mm) without bleed and 0.375" (9.6 mm) with bleed. They don't need to match each other.

With bleed, the page gets 0.125" wider (outside edge only) and 0.25" taller (top and bottom):

page width = trim width + 0.125
page height = trim height + 0.25

Worked examples

6" x 9" novel, 320 pages, no bleed. The PDF page is 6" x 9". The gutter must be at least 0.625" because 320 pages falls in the 301-500 band, and the other margins at least 0.25". That leaves a text block of up to 5.125" x 8.500".

8.5" x 11" workbook, 120 pages, with bleed. The PDF page is 8.625" x 11.25". Gutter at least 0.375", other margins at least 0.375".

Setting this up in Word, Affinity or InDesign

Set the document page size to the PDF page size above, turn on mirrored (facing) margins so the gutter alternates between left and right pages, and type the inside margin into the "inside" field. In Word this is under Layout → Margins → Custom margins → Multiple pages: Mirror margins. Export to PDF with fonts embedded. If you write the book first and pick margins later, check the page count again: wider margins add pages, and more pages can move you into a wider gutter band.

Frequently asked questions

What is the gutter margin?

The gutter (inside margin) is the margin on the side of the page that goes into the binding. Thicker books curve more at the spine, so KDP requires a wider gutter as the page count goes up.

When do I need bleed on the interior?

Only if any image, colour or shape runs to the edge of the page. If all your content sits inside the margins, choose "No bleed"; it is simpler and the page size equals the trim size.

Are these minimums or recommendations?

They are KDP's minimums. Most novels look better with more space, for example 0.75" to 1" outside margins on a 6" x 9" book. Going below the minimum gets your file rejected.

Does bleed change my trim size in KDP?

No. You still pick the normal trim size (for example 6" x 9") and choose "Bleed" in the print options. Only the PDF page size gets bigger.

Sources

KDP: Set trim size, bleed and margins

Rates last checked against KDP's help pages on 2026-10-16.