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5.5″ × 8.5″ Trim Size Guide

The most popular indie publishing trim size. Everything you need to know about margins, page count, spine width, and typography for 5.5 × 8.5 books on KDP and IngramSpark.

Overview

The standard trade paperback

5.5″ × 8.5″ is the default trim size for indie publishing. It is the most common size on Amazon KDP, the most frequently recommended in author communities, and the size that works for virtually every genre of fiction and most narrative nonfiction.

It is large enough to be comfortable to read but small enough to feel like a real novel, not a textbook. Page counts land in the sweet spot where printing costs stay reasonable and the book looks substantial on a shelf. If you are publishing your first book and have no strong reason to choose something else, this is the safe default choice.

This guide covers the specifications you need: KDP margin requirements, recommended margins for a professional interior, page count estimates by word count, spine width calculations, and typography guidance. Use our KDP Book Calculator to plug in your exact word count and get precise numbers.

KDP Requirements

Minimum inside margins

Amazon KDP requires larger inside (gutter) margins as page count increases. These are the minimums — your actual margins should be larger for a professional result.

Page Count KDP Min. Inside Margin
24 – 150 pages 0.375″
151 – 300 pages 0.500″
301 – 500 pages 0.625″
501 – 700 pages 0.750″
Outside margins. KDP requires a minimum outside margin of 0.25″ on all sides (top, bottom, and outside edge). These minimums are the same regardless of page count. Do not use these minimums for your final interior — they produce cramped, unprofessional-looking pages.
Professional Layout

Recommended margins

These ranges produce a well-proportioned text block that looks traditionally published. Use wider values for longer books.

Margin Recommended Range Notes
Inside (gutter) 0.75″ – 0.85″ Keeps text clear of the spine crease
Outside 0.50″ – 0.65″ Comfortable thumb room
Top 0.60″ – 0.75″ Allows space for running heads
Bottom 0.70″ – 0.85″ Slightly larger than top for visual balance

Calculate your exact margins and page count →

Page Count

Word count to page count

Estimates assume 11pt body text, professional serif font, ~1.4× leading, and standard margins. Includes front and back matter. Actual counts vary by font, chapter breaks, and scene break styling.

Word Count Approx. Pages Typical Genre
50,000 words ~190 pages Novella, short romance
60,000 words ~225 pages Category romance, cozy mystery
70,000 words ~260 pages Thriller, mystery
80,000 words ~280 pages Standard fiction
90,000 words ~320 pages Fantasy, historical fiction
100,000 words ~355 pages Epic fantasy, literary fiction
120,000 words ~425 pages Long fantasy, saga

Get your exact page count →

Cover Design

Spine width calculation

Your cover designer needs the spine width to build the cover template. The calculation depends on the paper stock:

Cream / off-white paper

Spine width = page count × 0.0025″

280 pages → 0.700″ spine

White paper

Spine width = page count × 0.002252″

280 pages → 0.631″ spine

Cream vs. white. Cream (off-white) paper is standard for fiction because it reduces eye strain. White paper is typical for nonfiction, especially books with images. Cream paper is thicker, so the spine is slightly wider for the same page count. Most KDP fiction authors choose cream.
Typography

Font size and spacing

Setting Recommendation
Body font size 11pt – 12pt
Font family Any professional serif (Garamond, Crimson, Minion, Baskerville)
Line spacing (leading) 1.3× – 1.5× font size
Paragraph indent 0.25″ – 0.35″ (first line)
Chapter title size 18pt – 24pt

At 5.5″ × 8.5″, the text block is wide enough for comfortable reading at 11pt but narrow enough that 12pt does not feel oversized. If in doubt, start at 11pt with 1.4× leading — this is the most common configuration for indie fiction and produces a result that matches traditionally published trade paperbacks.

Avoid sans-serif fonts for fiction body text. They work for headings, but serif fonts are the convention for novel interiors and produce better readability at long reading lengths. See our book font guide for specific recommendations.

The Default Choice

Why 5.5 × 8.5 works for almost everyone

Every trim size involves trade-offs. Here is why 5.5″ × 8.5″ sits at the center of those trade-offs for most indie authors:

vs. 5″ × 8″

The 5 × 8 mass-market size is great for genre fiction (romance, thriller, mystery), but the smaller page means more pages for the same word count, which increases printing costs. 5.5 × 8.5 gives you 15-20% fewer pages and a slightly more open text block, while still feeling like a compact novel.

vs. 6″ × 9″

The 6 × 9 format is the standard for nonfiction and literary fiction. It reduces page count (and print cost) but the book feels larger and more serious. For genre fiction, 6 × 9 can feel like a textbook to readers who expect a novel. If you are publishing nonfiction, 6 × 9 is often the better choice.

Reader expectations

Walk into any bookstore and pick up a trade paperback novel. Chances are it is close to 5.5″ × 8.5″. Readers have internalized this size as "novel." When your book matches that expectation, it looks and feels professionally published from the moment someone holds it.

Universal compatibility

5.5 × 8.5 is supported by every major print-on-demand service: Amazon KDP, IngramSpark, Barnes & Noble Press, and Lulu. You can use the same interior PDF everywhere. No reformatting required when you expand distribution.

For more on how different trim sizes compare, see our KDP trim sizes explained guide. If you are formatting for KDP specifically, our guides on formatting for KDP and formatting for IngramSpark walk through the full process.

Questions

Frequently asked

Is 5.5 x 8.5 the best trim size for self-publishing?
For most indie fiction, yes. 5.5" x 8.5" is the most popular trim size on KDP and IngramSpark because it balances readability, page count, printing cost, and shelf presence. It works for virtually every genre. Unless you have a specific reason to choose something else, 5.5 x 8.5 is the safe default.
What is the difference between 5.5 x 8.5 and 6 x 9?
A 6" x 9" book has a larger page area, so the same manuscript produces fewer pages — roughly 230 pages for 80,000 words vs. 280 pages at 5.5" x 8.5". The 6 x 9 format is standard for nonfiction and literary fiction, while 5.5 x 8.5 is the default for genre fiction and memoir. 6 x 9 also costs slightly less to print per copy because of the lower page count, but the book feels larger and more textbook-like for fiction readers.
What margins should I use for a 5.5 x 8.5 book?
KDP requires a minimum inside (gutter) margin of 0.375" for books under 150 pages, scaling up to 0.75" for books over 500 pages. For a professional result, use inside margins of 0.75" to 0.85", outside margins of 0.5" to 0.65", top margins of 0.6" to 0.75", and bottom margins of 0.7" to 0.85". These values give your text room to breathe and keep it away from the spine crease.
How many pages is 80,000 words in a 5.5 x 8.5 book?
At standard formatting (11-12pt serif, 1.3-1.5x leading, professional margins), 80,000 words produces approximately 280 pages in a 5.5" x 8.5" book. The exact count depends on your font, line spacing, chapter break styling, and front/back matter. Use a book calculator to get a precise estimate for your manuscript.
Does IngramSpark support 5.5 x 8.5?
Yes. 5.5" x 8.5" (sometimes listed as 5.5 x 8.5 or 139.7mm x 215.9mm) is a standard trim size on IngramSpark, available in both paperback and hardcover. It is also supported on KDP, Barnes & Noble Press, and Lulu. You can use the same interior PDF across all platforms.
What font size should I use for 5.5 x 8.5?
Use 11pt or 12pt for body text. 11pt is more common and produces a tighter, more professional look. 12pt works well for genres where readers prefer a larger type (cozy mystery, women's fiction). Pair with 1.3x to 1.5x line spacing. Any professional serif like Garamond, Crimson, or Minion will work. Avoid sans-serif for fiction body text.
Next Step

Know your specs?
Format the book.

Cambric applies the correct margins, fonts, and page layout for 5.5″ × 8.5″ automatically. Pick a template, import your manuscript, and export print-ready files.

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