Blankets for the smallest regular bed, a twin bed, are generally 66 inches by 90 inches, though exact sizes vary by manufacturer. Babies' mini cribs use smaller blankets, called stroller blankets, that measure about 30 inches by 35 inches. Receiving blankets are even smaller, at 23 to 30 inches square.
Blankets or quilts for baby dolls may be 12 inches by 16 inches or even smaller, depending on the size of the doll. These are usually handmade rather than manufactured for purchase at a store.
For a mattress of a given size, the proper fit size of a blanket is smaller than that of a comforter, which is smaller than that of a bedspread.