How Big Will My Puppy Get?

Growth Curves Help Predict Puppy's Size When Grown

May 6, 2008

A few tips can help in predicting a puppy's size at maturity, a big factor in deciding whether or not to adopt.

Everyone who adopts a puppy wants to know how big it will get. Since adopting a dog means making a commitment for its care and well being for the next 10 to 15 years, it’s wise to know whether you will end up with a big dog who needs plenty of room and a large food bowl to fill or a little dog who can get by in a tiny apartment with a small food bowl. And since most preventatives and medication dosages go by weight, this is a consideration too. If you have small children, a large dog may be too much for them while a very small dog may be too frail for their play. But it’s not always easy to know how big the puppy will be when grown.

Weight of Purebred Dogs

Even though breed standards dictate size in purebreds, that standard is the ideal for that breed while individual purebred dogs can and do vary somewhat from that. However, the size of the parents is a good indication of how big the purebred puppy will get.

Weight of Mixed Breed Dogs

Mixed breeds are harder to predict, but there are a few things to consider when trying to determine how big your puppy will be at maturity. If both parents are available, their size will give a basic indication of how big their puppies will get. If both parents are small, the puppies will also be small. If both parents are large, the puppies will be large. But in cases where the parents are different sizes or heritage is unknown, a few other considerations can give you an idea.

Puppies do most of their growing in the first 6 months of life. After that, growth slows until maturity which occurs at around one year of age, depending on the breeds involved. Smaller breeds reach maturity quicker than larger breeds. A puppy weighing 30 lbs at 3 months or 60 lbs at 6 months may grow to be near 100 lbs. In contrast, a puppy weighing 4 lbs at 3 months or 8 lbs at 6 months will likely reach maturity at under 12 lbs. A puppy weighing 15 lbs at 3 months or 30 lbs at 6 months may mature in the medium size range of 35 to 50 lbs. If the puppy’s age is unknown, that can be estimated by looking at its teeth.

Growth Plates and Height

Height is measured from the floor to the top of the shoulder. Since growth plates of the long bones in puppies stop growing at around the 8th to 12th month (longer in large breeds), most puppies have reached ¾ of their adult height by the age of 6 months.

These tips will not give an accurate prediction of a puppy’s size at maturity but should offer an approximation that will help in deciding if the puppy is right for you.