Last reviewed by The publishing.co.uk Team — May 2026
Use this calculator to find the exact gutter margin Amazon KDP requires for your paperback. Enter your page count below and get instant results based on Amazon's official margin requirements.
UK note: UK-specific considerations apply — ISBN purchases go through Nielsen (not Bowker), VAT rules differ from the US (print books are zero-rated; ebooks carry 20% VAT), and GDPR applies to any email/customer data. See our UK self-publishing guides for specifics.
Amazon KDP Gutter Margin Table (Complete Reference)
This is the complete gutter margin table Amazon uses for all KDP paperbacks. The gutter margin increases with page count because thicker books require more binding space.
| Page Count | Gutter Margin (inches) | Gutter Margin (mm) |
|---|---|---|
| 24 – 150 pages | 0.375" | 9.53 mm |
| 151 – 300 pages | 0.500" | 12.70 mm |
| 301 – 500 pages | 0.625" | 15.88 mm |
| 501 – 700 pages | 0.750" | 19.05 mm |
| 701 – 828 pages | 0.875" | 22.23 mm |
Outside margins are a minimum of 0.25" (6.4 mm) for all trim sizes and page counts. For books with bleed, add an extra 0.125" (3.175 mm) on the outside edges.
How Gutter Margins Work
The gutter margin is the space between your text block and the spine of the book. As your book gets thicker (more pages), more of the interior page gets "swallowed" by the binding. Amazon requires larger gutter margins for thicker books to ensure text remains readable near the spine.
Recommended Margins for Professional Results
While Amazon specifies minimum margins, professional books typically use more generous spacing. Here are our recommendations for the most popular trim sizes:
| Trim Size | Recommended Outside | Recommended Top/Bottom | Gutter |
|---|---|---|---|
| 5" x 8" | 0.5" (12.7 mm) | 0.5" (12.7 mm) | KDP minimum + 0.125" |
| 5.5" x 8.5" | 0.5" (12.7 mm) | 0.625" (15.9 mm) | KDP minimum + 0.125" |
| 6" x 9" | 0.625" (15.9 mm) | 0.75" (19.1 mm) | KDP minimum + 0.125" |
| 7" x 10" | 0.75" (19.1 mm) | 0.75" (19.1 mm) | KDP minimum + 0.125" |
You might also need
- Spine Width Calculator
- Royalty Calculator
- KDP Trim Size Guide
- KDP Formatting Checklist
- Word to KDP Guide
Frequently asked questions
What's the most common mistake first-time authors make with kdp margin calculator?
Skipping the verification step. Most kdp margin calculator problems are caught by a 10-minute pre-flight check before upload — we see this in our formatting queue every week.
How much time does kdp margin calculator usually take?
Allow 2-8 hours for a first attempt, 30-60 minutes once you've done it twice. The first time eats time because you're learning the controls; subsequent times are mechanical.
Are the free tools good enough or should I pay?
Free tools work if you have time to learn them. Paid tools (or services) save 10-30 hours and reduce rejection rates. Worth it if you're launching multiple titles.
Where can I check my work before going live?
Run a free KDP Readiness Score — catches 35+ common issues in 60 seconds, no signup. If anything fails, the report tells you exactly what to fix.
Further reading from official sources
- KDP — Paperback manuscript formatting — official trim and margin requirements.
Related Tools
About this guide
Written by The publishing.co.uk Team for publishing.co.uk. Last reviewed May 2026. Specs and pricing change — verify current figures with the linked sources before relying on them.
External references
- For current UK indie publishing trends, see the ALCS Author's Earnings report.
