According to the Wikipedia entry,
“The American Kennel Club recognizes two separate varieties of Beagle: the 13-inch for hounds less than 13 inches (33 cm), and the 15-inch for those between 13 and 15 inches (33 and 38 cm). The Canadian Kennel Club recognizes a single type, with a height not exceeding 15 inches (38 cm). The Kennel Club (UK) and FCI affiliated clubs recognize a single type, with a height of between 13 and 16 inches (33 and 41 cm).”
Beagles can be placid. Check out those beautiful eyes.