When you want to know big your puppy will get, there are ways – though not necessarily easy ones if your puppy is a mixed breed–to determine approximately what size he will grow to be when he reaches adulthood. The younger your dog is, the more difficult it will be to assess his potential adult size.
If you are able to see both of your puppies’ parents, this can help a lot in giving you an idea of what his adult size may be. If you do have access to the parents and they are approximately the same size, in all likelihood your pup will grow to about the same. But what if you don’t know what the size of the parents? Or perhaps you only know the size of the mother? If you don’t know both puppies parents sizes, there are a few other indicators that you can look at that may clue you in to your dog’s future adult size.
One that most people already know about is paw size. Like people, the bigger the feet, the taller one is likely to become. You can also take a look at your puppy’s skin to see how loose it is; the looser it is, the larger he will likely become. Your puppy will grow into this extra skin as he gets older, so the bigger he is going to get, the more loose skin he will probably have. This can be a fairly good indicator of how big your puppy will get.
The growth plates in your dog will close between 8 and 11 months at which point he won’t get any taller, but will continue to increase in bulk until his full adult weight is reached. A good way to estimate what the height of your adult dog will be is to look at how large he is at 6 months. There is also what is called a “double-it” formula. Using this formula, you weigh your puppy at 14 weeks; whatever he weighs at that time, he will weigh approximately double it when he is at his full-grown adult dog weight.
You can also, however, utilize a growth curve formula to estimate your puppy’s eventual full-grown size. From birth to 6 months is the most rapid of growth periods for a dog. After this period, his growth will slow and then halt between 8 and 14 months of age. You can use either height, which is measured to the shoulder, or weight to plot your puppy’s growth and assess it at various intervals in order to determine what his adult height and/or weight will be.
If you mark his growth on a chart, you will see an actual curve. This curve will reach the “knee” at about 65% of your dog’s eventual adult size and then plateau when he has reached approximately 95% of the size he’ll be when he’s full grown. Though there really is no way to estimate with 100% accuracy how large your puppy will be when he’s a full grown adult dog, these methods will certainly give you a good indication.