KDP Margin & Gutter Calculator
Find the minimum inside gutter and outside margins for your page count and trim size — and the live area your artwork must stay inside.
Minimum inside (gutter) margin
0.375" (9.52 mm)
Minimum outside margins (no bleed)
0.25" (6.35 mm)
Live area at minimum margins
7.875" (200.02 mm) × 10.5" (266.7 mm)
Your page count falls in the 24–150 page tier. At 151+ pages the minimum gutter becomes 0.5". Margins are measured from the trim edge; these are minimums — larger margins are always safe.
Data source: spec version kdp-spec-2026-08, last verified against the official KDP help pages on .
KDP can change its specifications at any time — always confirm against the official pages before uploading. This tool gives print-spec math only; it does not guarantee KDP acceptance. All calculations run in your browser and nothing you enter is uploaded or stored.
How the KDP margin & gutter calculator works
KDP publishes minimum margins that depend on page count and bleed. The inside (gutter) margin grows with page count because thicker books lose more of the page to the binding:
| Page count | Minimum gutter |
|---|---|
| 24–150 pages | 0.375" (9.5 mm) |
| 151–300 pages | 0.5" (12.7 mm) |
| 301–500 pages | 0.625" (15.9 mm) |
| 501–700 pages | 0.75" (19.0 mm) |
| 701–828 pages | 0.875" (22.2 mm) |
Outside/top/bottom margins must be at least 0.25" without bleed or 0.375" with bleed. The live area is what remains of the trim after subtracting the gutter on one side and the outside margin on the other three.
Worked example: 100-page 8.5" × 11" book, no bleed
100 pages falls in the 24–150 tier, so the gutter minimum is 0.375" and the outside minimum is 0.25". Live area: width 8.5 − 0.375 − 0.25 = 7.875", height 11 − 0.5 = 10.5". If the book later grows to 151 pages, the gutter minimum becomes 0.5" and the live area narrows to 7.75".
Common mistakes
- Crossing a gutter tier late in production. Going from 150 to 151 pages raises the required gutter — near a boundary, design for the larger tier from the start.
- Confusing document margins with content position. A margin error usually means repositioning artwork inside the live area, not just changing a setting at export.
- Forgetting that bleed raises the outside minimum. With bleed on, content must stay at least 0.375" (not 0.25") from the trim edge.
- Mirroring margins incorrectly. The gutter alternates sides: right edge on left-hand pages, left edge on right-hand pages. Use mirrored/inside-outside margins.
Frequently asked questions
- How much gutter does my KDP coloring book need?
- The minimum inside (gutter) margin depends on page count: 0.375" up to 150 pages, 0.5" for 151–300, 0.625" for 301–500, 0.75" for 501–700 and 0.875" for 701–828 pages. Outside margins must be at least 0.25" without bleed or 0.375" with bleed.
- Why did the gutter change at a higher page count?
- Thicker books curve more at the binding, so KDP requires a larger inside margin as page count grows. Crossing a tier boundary — for example going from 150 to 151 pages — raises the minimum gutter and can push existing artwork outside the allowed area.
- What does "text or images outside the margin" mean?
- It is KDP's review error for content that sits closer to the page edge (or gutter) than the minimum margins allow. Fixing it usually means repositioning or scaling the affected content — simply changing an export setting does not move artwork back inside the live area.
- Is gutter the same as inside margin?
- Yes — the gutter is the inside margin along the binding edge. In your layout software, set the document's inside/gutter value to at least the number this calculator shows for your page count.