Book Sizes

Scale of the American Library Association

Size Name	Symbol	Outside Height*	Appx Size in Inches*
folio	F	over 30 cm	12 x 19
quarto	Q	25-30 cm	9½ x 12
octavo	O	20-25 cm	6 x 9
imperial octavo	O	-	8¼ x 11½
super octavo	O	-	7 x 11
royal octavo	O	-	6½ x 10
medium octavo	O	-	6 1/8 x 9¼
crown octavo	O	-	5 3/8 x 8
duodecimo	D	17.5-20 cm	5 x 7 3/8
duodecimo (large)	D	17.5-20 cm	5½ x 7½
sextodecimo	S	15-17.5 cm	4 x 6¾
octodecimo	T	12.5-15 cm	4 x 6½
trigesimo-segundo	Tt	10-12.5 cm	3½ x 5½
quadrasegisimo-octavo	Fe	7.5-10 cm	2½ x 4
sexagesimo-quarto	Sf	less than 7.5 cm	2 x 3

*Outside height refers to the head-to-foot dimension of the book's cover
*Approximate Size refers to the front cover's rectangular dimensions

The common book-trade designation of sizes was originally related to a sheet of handmade paper measuring 19 X 25 inches, which was the common size of the papermaking mold. When folded to 8 leaves, or 16 pages, and trimmed, each was 6½ X 9¼ inches, approximately, and was the standard dimension of an 8vo. When folded to make 16 leaves, or 32 pages, it was a 16 mo. With the present great variety of paper sizes, all dimensions are by necessity only approximate. (52, 69, 140, 156, 169) 

British book sizes

Size Name	Octavo Size	Quarto Size
pott	6¼ by 4	8 by 6¼
foolscap	6¾ by 4¼	8¼ by 6¾
crown	7½ by 5	1O by 7½
large crown	8 by 5¼	10½ by 8
large post	8¼ by 5¼	10¼ by 8¼
demy	8¾ by 5 5/8	11¼ by 8¾
post	8 by 5	10 by 8
small demy	8½ by 5 5/8	11¼ by 8½
medium	9 by 5¾	11½ by 9
small royal	9¼ by 6 1/8	12¼ by 9¼
royal	10 by 6¼	12½ by 10
super royal	10¼ by 6¾	13½ by 10¼
imperial	11 by 7½	15 by 11

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