What are the standard book sizes for trade paperbacks?

The four standard US trade paperback sizes are 5 x 8 in (compact fiction and romance), 5.25 x 8 in (literary and mystery fiction), 5.5 x 8.5 in (digest trade fiction and memoir), and 6 x 9 in (US trade standard for long fantasy, sci-fi, thrillers, and nonfiction).

How much money does switching from 5x8 to 6x9 save on KDP printing costs?

For an 85,000-word novel, moving from 5 x 8 in (~354 pages) to 6 x 9 in (~280 pages) reduces the interior by ~74 pages. At KDP's $0.012 per-page rate, that saves $0.89 in printing cost on every paperback sold—or $445 per 500 copies.

Why does changing trim size in Word break my book layout?

When you change page dimensions in Microsoft Word, your inside gutter margin frequently falls below KDP's new page-count bracket, running headers de-center, and manual page breaks leave half-empty pages. In Cambric, switching trim size recomposes the entire book on live pages automatically.

Free Tool — Trim Size & Cost Optimizer

Standard Book Sizes & Trim Size Calculator

Select your genre and word count to compare all four standard trade paperback sizes side by side—including estimated page count, KDP inside gutter bracket, spine width, and per-copy printing cost.

Your Manuscript

Primary genre

Word count

Paper stock

Genre & Length Recommendation

Recommended: 6" × 9" (US Trade)

At 95,000 words, 6" × 9" keeps your paperback around 312 pages with a comfortable 0.625" inside gutter and saves $0.86 per copy compared to a 5" × 8" edition.

Side-by-Side Comparison Across All 4 Standard Trade Sizes

Standard Trim Size	Est. Pages	KDP Min Gutter	Spine Width	KDP Print Cost

Why You Cannot Test Trim Sizes Properly in Word

An estimate cannot show you where your chapter titles, scene breaks, and widows land.

Changing a document from 6" × 9" to 5.5" × 8.5" in Word forces you to rebuild your inside gutter bracket (0.500" vs 0.625"), re-center running headers, and hunt down dozens of newly stranded scene breaks and two-line page endings by hand.

In Cambric, switching trim size is one click on live pages:

Open your book in Cambric's local desktop workspace on Windows or Mac. Click between 5" × 8", 5.25" × 8", 5.5" × 8.5", and 6" × 9" and watch the entire manuscript recompose in seconds—with mirrored gutters, running headers, drop caps, and widow/orphan control updated automatically. Export print-ready PDF and EPUB 3 from the same book.

Test Trim Sizes Live in Cambric ($199 One-Time) → Browse 20+ interior templates Read Trim Size Guides