Here is a chart of the current (Jan 2019) CS/Kindle Direct trim sizes for books.


Trim sizeBlack ink and white paperBlack ink and cream paperColor ink and white paper
5" x 8" (12.7 x 20.32 cm)24 - 82824 - 77624 - 828
5.06" x 7.81" (12.85 x 19.84 cm)24 - 82824 - 77624 - 828
5.25" x 8" (13.34 x 20.32 cm)24 - 82824 - 77624 - 828
5.5" x 8.5" (13.97 x 21.59 cm)24 - 82824 - 77624 - 828
6" x 9" (15.24 x 22.86 cm)24 - 82824 - 77624 - 828
6.14" x 9.21" (15.6 x 23.39 cm)24 - 82824 - 77624 - 828
6.69" x 9.61" (16.99 x 24.41 cm)24 - 82824 - 77624 - 828
7" x 10" x (17.78 x 25.4 cm)24 - 82824 - 77624 - 828
7.44" x 9.69" (18.9 x 24.61 cm)24 - 82824 - 77624 - 828
7.5" x 9.25" (19.05 x 23.5 cm)24 - 82824 - 77624 - 828
8" x 10" (20.32 x 25.4 cm)24 - 82824 - 77624 - 828
8.25" x 6" (20.96 x 15.24 cm)24 - 80024 - 75024 - 800
8.25" x 8.25" (20.96 x 20.96 cm)24 - 80024 - 75024 - 800
8.5" x 8.5" (21.59 x 21.59 cm)24 - 59024 - 55024 - 590
8.5" x 11" (21.59 x 27.94 cm)24 - 59024 - 55024 - 590
8.27" x 11.69" (21 x 29.7 cm)24 - 78024 - 730Not available