HOW BIG WILL MY PUPPY BE WHEN FULL GROWN?
How big will my puppy get? Almost the first question anyone asks when thinking about adopting or buying a puppy is "How big will he get?" This is an important question to think about when you are considering adding any breed into your home. Looking up breed standards is a good place to start; books such as the American Kennel Club's Complete Dog Book have lots of valuable information about each breed, including average size.
Height ranges according to the breed standard. Most people assume their puppy will grow to within these acceptable ranges. Though height does get asked about, when people ask "How big will my dog get?" for the most part what they really want to know is weight.
What about your puppy? Will your puppy be 4 pounds or 14? How can you tell? You may get some idea by looking at the puppy's parents. You may also get clues by seeing several other dogs in your puppy's breedline and by talking to your breeder who knows their line best and how puppies in the past have matured. If that is not enough for you, here are a few insights to give you a handle on a puppy's growth potential; estimating a puppy's eventual size is not as tricky as it seems. Looking at weight at specific ages is one of the simplest methods.
The younger a puppy is, the harder it is to predict what size it will eventually be. Birth weights are the least value of all in predicting adult size. Actually, anything less than 8 weeks gives a pretty unreliable answer. Weight estimates before the age of 8 weeks give erratic results in large part because puppies are still nursing or being weaned. Nursing puppies may be heavier because of the high calorie/high fat content of mother's milk. Puppy weights in these early weeks also depend on the size of the litter. A singleton puppy that has all the milk to himself may have a much sharper weight gain than a puppy having to share the buffet with 6 litter mates.
When predicting adult size, the two easiest formulas to remember are FOUR FOLD and DOUBLE UP. Four Fold: The weight of a healthy puppy at 8 weeks of age is approximately one quarter of adult weight. Double Up: The weight of a healthy puppy at 16 weeks is approximately one half of adult weight. The 16 week weight calculation is more reliable than the 8 week one. The 8 week calculation is reasonably accurate to within +/- 15% while the 16 week calculation is +/-10%.