Size classifications of Dahlias

AA (Giant) over 10″ diameter
A (Large) 8-10″ diameter
B (Medium) over 6 to 8″ diameter
BB (Small) over 4 to 6″ diameter
M (Miniature) up to 4″ diameter
BA (Ball) over 3.5″ diameter
MB (Miniature Ball) over 2 to 3.5″ in diameter
P up to 2″ in diameter
MS (Mignon Single) up to 2″ in diameter
S over 2″ in diameter