Few things are more exciting than bringing home a puppy. This tiny dog will soon become a big part of your life, often with an emphasis on the word ‘big’. As much as you might love your little boy or girl, you do have to face the fact that he or she isn’t going to stay small for long. That, perhaps, is why so many dog owners immediately start looking at how big their puppies might get as soon as their dogs come home.
There are, of course, many great reasons to figure out how big your puppy is going to get. Most dog accessories are based on size and having at least some idea of how big your puppy is going to grow allows you to do a lot of planning. This is also a vital step that you’ll have to take to make sure that you have the best dog crate for the breed that you want to adopt, as dogs of certain sizes really do need more space than others.
The good news for at least some dog owners is that you’ll always be able to roughly calculate how big a purebred pup is going to get. While there are certainly outliers for every breed, you should be able to figure things out within a certain range of length and weight. For the rest of us, though, the work that goes into figuring out when a puppy will stop growing involves more guesswork.
If you’ve got a mixed-breed puppy, you can still make some great estimates as to how big he or she is going to get as long as you can take a few factors into account. The first thing you’ll need to know is how long puppies take to grow, while the second is your puppy’s current weight. From here, you can start to get a rough idea of how large your puppy is likely to get when he or she reaches full size.
Puppies and Growth
Puppies actually grow at very different rates. You might have bought what you assumed to be a small dog, but he or she can grow impressively over a long period of time. Likewise, you might get what you think is a big puppy only to find out that you’ve actually rescued an older dog that has reached his or her full size. Having a good idea of what your puppy’s growth—or lack thereof—means for the future is always helpful.
Typically speaking, the breed of your dog is going to influence not only his or her size but also the rate at which he or she grows. If you’ve adopted what you think is a bigger breed, you might be in for a continuous growth process that lasts for up to two years. If you’ve adopted what you think is a toy breed, on the other hand, you should expect the dog to stop growing at about the six-month mark.
If you have a puppy that seems to keep gaining weight and getting bigger after a year, you should start doing some research into his or her parentage. The odds of the dog being a bigger breed than you may have expected are high and you might need more room than you planned on having. Your puppy’s rate of growth is, however, just one of the factors that will influence how big he or she gets.
Puppy Weight and Size—How Big Will My Puppy Get?
In addition to clocking the rate at which a dog grows, you’ll also want to spend some time looking at your pup’s current weight to determine how big he or she will get when he or she reaches full size. There are a few different methods that you can use here, but two of them tend to be a little more accurate than the others.
Weight Gain and Adult Size
The first thing you’ll look at when trying to figure out your dog’s final size is looking at the speed at which he or she gains weight. This is easiest to determine by starting with your puppy at birth, as you can expect your puppy to double in weight after about one week. From that point, you should expect your puppy to gain between five and ten percent of his or her body weight every week regardless of breed.
Things start to change at six weeks, though. If you’re looking at a small breed, you should be able to reliably expect him or her to start gaining about five ounces a week. If you’re looking at bigger breeds, though, you will see him or her gain around two and a half pounds per week. You can further use these expectations to figure out exactly how your dog is going to grow.
If you’re looking at a small or toy breed, you can actually make a very safe assumption about your puppy’s adult weight based on how much he or she weighs at the six-week mark due to the slow but steady rate of weight that he or she will gain. At six weeks, your puppy should be about a quarter of what he or she will weigh at adult size. A puppy who is two pounds at six weeks old should be on track to weigh about eight pounds as an adult.
Bigger breeds require a bit more math than their counterparts. While you can still use the six-week point as to where you want to start if you’re willing to diligently add up the pounds, it’s usually easier to weigh your dog at the fourteen-week point. You’ll then double that weight and then add half of the fourteen-week weight together to get an idea of what your dog will weigh when he or she is an adult.
Let’s say, for example, that your big puppy already weighs thirty pounds at fourteen weeks. You’ll then double that weight (30+30) and add together half of the original weight (15) to get the estimate of the puppy’s final adult weight (75 pounds).
As a note, though, the giant breeds grow even more slowly and require another way to guess their adult weight. Extra large dog breeds like St. Bernards hit half their adult rates at about six months . Thus, you can take the puppy’s weight at six months and double it to figure out exactly how much he or she should weigh as an adult.
Estimating Size Later
Unfortunately, not everyone gets to be with their puppies from birth. Many owners, in fact, might not even be around their puppies at the six-week mark. As you can imagine, this makes it impossible to use the math above to properly guess how big your puppy is going to get.
Luckily, there is an alternative way to figure out how big your dog is going to get based on his or her weight. The only things you’ll need to know are the age of the dog, the assumed breed of the dog, and when you’re taking the measurements, and the dog’s current weight.
The math here isn’t too tough. You’ll take the weight of the puppy at the breed-specific time, divided by the dog’s age, and then multiplied by fifty-two. This will give you a rough estimate of how much your dog is going to weigh as an adult.
The reason why you need to know the dog’s breed is to figure out exactly when he or she needs to be weighed. The genetic makeup of a mixed-breed can be determined using a dog DNA test. If you are looking at a small or toy breed, you should try to weigh him or her at the twelve-week mark. If the dog is medium-sized, you’ll weigh him or her at the sixteen-week mark. The biggest breeds, however, need to weigh until they are about twenty weeks old in order to get a good measurement.
Let’s do a little bit of math with the assumption that you are looking at a bigger breed.
In this situation, we will assume that your dog weighs around twenty pounds when he or she is sixteen weeks old. We now have all the numbers we need to plug into our formula.
We’ll start by taking the dog’s weight (twenty pounds) and divide that by his or her age (sixteen). What we’re looking at, then, is 10/16, or 1.25. Now we will take that product and multiply it by the number of weeks in a year (52). That means our formula now looks like (1.25) x (52), which gives us a product of 65 pounds as our dog’s theoretical adult size.
Small dogs are just as easy to work with. Let’s say your dog weighs one pound at week twelve. Plugging it into our formula means we are going to divide one by twelve (1/12, or about .84) and then we’ll multiply that by fifty-two (.84 x 52) to get the dog’s assumed adult weight at about 4.3 pounds.
Secondary Factors to Predict Growth
While the two factors above are certainly the most important for predicting how big your dog is going to get as he or she ages, there are a few other factors that will help you to further determine whether your dog will be towards the big or small end of his or her breed’s size.
The first one is the easiest—gender. Male dogs tend to be bigger than females, though not always to an immense degree. Though this can vary by breed, you should generally expect your male dog to be bigger than a female.
You should also take a look at when your dog was spayed or neutered. It turns out that dogs who get spayed or neutered actually tend to be taller than their counterparts, if not necessarily heavier.
Breed matters, too. Toy breeds are only going to get up to a certain size, while you can reliably count on your giant dog to get very big. While there’s always some room for variation within breeds, you can get an upper and lower limit of how large your dog is likely to be.
Finally, you’ll want to take a look at your dog’s parents if possible. Whether you owned the parents or you just have paperwork, looking at the size of the parents is usually a good way to figure out how big your dog is likely to be. This is perhaps the easiest way to estimate size, but it’s also one that’s not necessarily going to be possible for everyone.
As an aside, you should really try to ignore the old saws about the size of your puppy’s foot determining how big he or she will get later in life. While bigger breeds certainly have bigger feet, you can never really tell how each part of your puppy is going to grow. Your puppy’s big paws might have just started growing before the rest of him or her, which means that you could just have an awkward puppy for a bit while the rest of his or her body catches up.
Frequently Asked Questions
How can I estimate my dog’s size?
There are several different ways to estimate your puppy’s size. The easiest way is to look at his or her parents as a guide. If you have never seen the parents, though you can generally make an informed guess based on your dog’s breed. Not sure of the breed? If that’s the case, you’re going to have to dig a little deeper. Pay attention to how fast your puppy is growing so that you can estimate how much weight he or she will continue to put on. If you have a good idea of the general types of a breed that make up your dog’s background, you can also use a simple mathematical formula to guess how big he or she will get.
How big will my dog be fully grown?
This depends on a number of factors. Everything from your dog’s breed to his or her diet is going to impact how big your dog gets. The best way to figure this out is to look at other dogs of a similar breed to get both an upper and lower limit of what you should expect from your dog as an adult.