Covers

Book Spine Width Charts by Trim Size & Page Count

Pick a trim size to see spine widths and full-wrap cover dimensions for page counts from 24 to 828.

Spine width (white paper) at a glance

Trim	100 pp	200 pp	300 pp	400 pp	500 pp
5 x 8 in	0.225 in	0.45 in	0.676 in	0.901 in	1.126 in
5.06 x 7.81 in	0.225 in	0.45 in	0.676 in	0.901 in	1.126 in
5.25 x 8 in	0.225 in	0.45 in	0.676 in	0.901 in	1.126 in
5.5 x 8.5 in	0.225 in	0.45 in	0.676 in	0.901 in	1.126 in
6 x 9 in	0.225 in	0.45 in	0.676 in	0.901 in	1.126 in
6.14 x 9.21 in	0.225 in	0.45 in	0.676 in	0.901 in	1.126 in
6.69 x 9.61 in	0.225 in	0.45 in	0.676 in	0.901 in	1.126 in
7 x 10 in	0.225 in	0.45 in	0.676 in	0.901 in	1.126 in
7.5 x 9.25 in	0.225 in	0.45 in	0.676 in	0.901 in	1.126 in
8 x 10 in	0.225 in	0.45 in	0.676 in	0.901 in	1.126 in
8.5 x 8.5 in	0.225 in	0.45 in	0.676 in	0.901 in	1.126 in
8.5 x 11 in	0.225 in	0.45 in	0.676 in	0.901 in	1.126 in

Choose a trim size

5 x 8 in 5 x 8 in 5.06 x 7.81 in 5.06 x 7.81 in 5.25 x 8 in 5.25 x 8 in 5.5 x 8.5 in 5.5 x 8.5 in Digest 6 x 9 in 6 x 9 in US Trade 6.14 x 9.21 in Royal (6.14 x 9.21 in) 6.69 x 9.61 in 6.69 x 9.61 in 7 x 10 in 7 x 10 in Executive 7.5 x 9.25 in 7.5 x 9.25 in 8 x 10 in 8 x 10 in 8.5 x 8.5 in 8.5 x 8.5 in Square 8.5 x 11 in 8.5 x 11 in Letter

How spine width is calculated

For print-on-demand paperbacks, spine width is the page count multiplied by the thickness of one page of the chosen paper:

spine = pages × paper factor

KDP publishes 0.002252 in per page for white paper, 0.0025 in for cream, 0.002252 in for standard colour and 0.002347 in for premium colour. Offset printers specify paper by PPI (pages per inch), in which case spine = pages ÷ PPI.

The full cover is bleed + back cover + spine + front cover + bleed wide and trim height + 2 × bleed tall.