There are two ways to predict size of a puppy. One is triple the three month weight. The other is to double the 4 month weight. I have found this is more accurate with smaller dogs. For Spot......... she was around 15 lbs at 3 months which would put her at around 60lbs adult weight. She isn't quite 4 months yet so if I add a couple of pounds to her current weight of 20 lbs (23lbs x 2) , that would be an estimate of 46 lbs adult weight. So, maybe between 46-60 lbs. I would think more towards the 60 as her mom was quite large.
