Book height (spine) = matching fabric book cover size
9.5"/24.1cm - for tall hardcovers
9"/22.9cm - for tall US paperbacks
8.5/ 21.6cm- for short hardcovers and 8.5" indie paperbacks; for US short paperbacks and B-format hardcovers
8"/20.3cm - for 8" Indie paperbacks.
🌟8'' size book cover can also be used as journal cover.