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

Duodecimo vs. Folio

Comparing 2 standards across 9 specifications. 9 key differences identified.

Comparing:
Duodecimo
Folio

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 Folio (abbreviated 2° or fo) is a traditional book format created by folding a full printer's master sheet (Broadside) in half once, producing 2 leaves (4 printed pages). Measuring approximately 12 × 19 inches (305 × 483 mm) or larger, it is historically reserved for monumental prestige publications, including the Gutenberg Bible (1455) and Shakespeare's First Folio (1623).

View full Folio spec sheet →

Specification Comparison Table

9 Parameters
Parameter / Spec
Folding Structure
Complex combination fold (often folding in thirds then quarters) 1 fold down the center of a full printer's sheet
Leaf and Page Yield
12 leaves (24 printed pages per sheet) 2 leaves (4 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)
Typical Historical Dimensions
Approx. 12 × 19 inches (305 × 483 mm) up to 15 × 20 inches
Signature Geometry
Broadside sheet folded into vertical folio signatures
Historical Milestone
Gutenberg 42-Line Bible (1455) / Shakespeare's First Folio (1623)
Modern Commercial Equivalent
Oversized coffee table art books, museum facsimile editions, archival atlases