# item.guide
Side-by-Side Comparison Book & Publishing Formats

Duodecimo vs. Mass Market Paperback

Comparing 2 standards across 12 specifications. 12 key differences identified.

Comparing:
Duodecimo
Mass Market Paperback

A Duodecimo (abbreviated 12mo or 12°) is a classical pocket book format created by folding a printer's sheet into 12 leaves (24 printed pages). Measuring approximately 4.75 × 7.5 inches (120 × 190 mm) or 5.0 × 7.75 inches, it was the historical ancestor of the modern paperback, widely used for personal devotional books, poetry collections, and traveler guides.

View full Duodecimo spec sheet →

A Mass Market Paperback (also known as a Pocket Book / Rack-Size Novel) is a standardized commercial book publishing format measuring 4.25 × 6.875 inches (108 × 175 mm). Engineered for high-volume rotary letterpress/web offset printing on groundwood pulp paper, it is designed to fit spinning wire display racks in airports, supermarkets, and drugstores.

View full Mass Market Paperback spec sheet →

Specification Comparison Table

12 Parameters
Parameter / Spec
Folding Structure
Complex combination fold (often folding in thirds then quarters)
Leaf and Page Yield
12 leaves (24 printed pages per sheet)
Typical Dimensions
Approx. 4.75 × 7.50 inches to 5.0 × 7.75 inches (120 × 190 mm to 127 × 197 mm)
Historical Significance
Aldine Press Renaissance pocket classics (Aldus Manutius, Venice, 1501)
Modern Equivalent
B-format paperbacks (5.1 × 7.8 in / 129 × 198 mm UK standard)
Width × Height (Imperial)
4.25 × 6.875 in
Width × Height (Metric)
108 × 175 mm
Paper Type
High-bulk mechanical groundwood pulp paper (uncoated, prone to yellowing)
Binding Style
Perfect Binding (cold EVA or hot PUR adhesive along trimmed spine)
Distribution Channels
Wire revolving racks in grocery stores, airport kiosks, newsstands
Strip-Cover Returns Policy
Unsold copies are 'stripped' (cover torn off for credit; body pulped)
Primary Genres
Thriller novels, romance, science fiction, crime paperbacks