Foldings Section Size Symbol Customary Leaves Pages Number of Folds Folio fo 1 2 4 Quarto 4to 2 4 8 Sixmo 6to varies 6 12 Octavo 8vo 3 8 16 Twelvemo 12mo varies 12 24 Sixteenmo 16mo 4 16 32 Eighteenmo 18mo varies 18 36 Twenty-fourmo 24mo varies 24 48 Thirty-twomo 32mo 5 32 64 Thirty-sixmo 36mo varies 36 72 Forty-eightmo 48mo varies 48 96 Sixty-fourmo 64mo varies 64 128