Standard: 21 to 24 inches from the wither to ground. The ideal size for the female is 21-23 inches and the male is 22-24 inches. Weight range tends to be about 55-75 lbs.
Medium: 17 to 21 inches from the wither to ground. The ideal size for the female is 17-19 inches and the male is 18-21 inches. Weight range is about 35-55 lbs.
Miniature: 14 to 17 inches from the wither to ground. There is no correlation between height and sex in the Miniature size. Weight range is about 15-35 lbs.
Second: What type are you looking for?
F1: First cross of poodle and lab. Will have some shedding but will not have the heavy under coat of a lab. Allergy friendly. Usually in medium to standard sizes.
F1B: The cross of a Labradoodle and a poodle. Will have very light shedding but not as much as an F1 or a Lab. More allergy friendly. Usually in medium to standard sizes.
Multi-gen: The cross of an F1B to another F1B. Little to no shedding and the most allergy friendly. Usually only in the medium to miniature sizes.