Just hear me out..... I know I go against the grain on this....everyone thinks "tiny" is better, but I disagree. I like a beagle that looks like a beagle. Uno is the standard now and I am happy about that. He is in the 15" category. He is not a miniature or pocket beagle, but the real thing; a relatively small dog in comparison to many breeds. The beagle has personality far bigger than his size, he is full of the independent and merry hound spirit, he is beautifully athletic, and one of the most loving creatures you will ever meet. They are born to be in a family, born to be part of the human pack, and born to be the best of companions.
We have a few smaller beagles. Maggie and Flick are quite small; Flick is 18 lbs and Maggie only 15 lbs. But they are not what I would call miniature. They are athletic, built to stand the chase a true hound is bred for, but they stand at 12 3/4 and 14" tall. They don't have the short legs of a miniature, but rather well-proportioned and elegant "running gear."
For my two cents worth, size should not be your only consideration when choosing your beagle puppy. And just because a puppy has small parents doesn't guarantee he will be small when he grows up (learned that one very well). For an animal that you will live with and love hopefully for many years, don't you want one that has the structure and muscle for years of active and healthy living? A well proportioned dog is more likely to be an athletic and healthy dog; an athletic and healthy dog will more likely be with you longer.... And isn't that what we all want?