How big will my puppy get?

18th Oct, 2016

Puppies are adorable. Puppies are bouncy. Puppies are love and joy personified. Indeed, puppies are many wonderful things – but one thing they usually are not is predictable, especially in what size they’ll be when they’re grown up, particularly if they’re mixed breeds.  

Why you need to know

Knowing what size a pup will be is important for several reasons. Dogs need to suit your lifestyle and income. For example, if you live in a small flat, a tiny dog is best; those living on smallholdings or farms may prefer big dogs. Also, some rental properties or complexes don’t allow dogs over a certain size.

Frail, physically handicapped, or elderly people could be knocked over or hurt by a large, rambunctious dog; tiny dogs could be hurt by small children, or get underfoot of people who struggle to walk. If you’re adopting a friend for an existing, large-breed dog, a miniature may not work – and vice versa. Giant dogs cost more in terms of food, accessories, etc.  

Size also affects potential future health problems; for example, large breeds frequently have hip or cruciate ligament problems, whilst mini breeds tend towards breathing and digestive issues. Larger dogs also live shorter lives than small ones. Clearly, having some idea of eventual size is a necessary part of choosing a puppy.

Crystal ball

If your pup is purebred, you can predict its eventual size fairly accurately. Mixed-breed pups are a little more challenging, especially if you don’t know anything about either parent, or only know about the mother. Even when you do know what both parents look like, dogs can have puppies from different fathers in one litter, resulting in variation in size and appearance; unless you’re completely sure no other males were involved, you still can’t be sure the pups will all be the same. There can also be ‘throwbacks’ to the various breeds in their genetic makeup, so that two smaller mixed-breed dogs can have a larger puppy. If the parents come from an impoverished environment, they may be smaller than they should have been due to malnourishment.

Fortunately, despite all the unknown factors, it is still possible to get a general idea of size, especially in slightly older pups. Here’s how:

  • Establish age. By four to six months, puppies will be around 65% of their adult height and 30% of adult weight. Small to medium breeds reach full size at around nine to ten months old, large pups keep growing until 12 to 18 months, and very large and giants can continue growing until two or three years old.
  • Looking at their teeth can provide an indication of age. Pups usually get baby teeth – which look more ‘serrated’ than the smoother adult teeth – at around two to three weeks old, starting with incisors, then canines, then premolars (they don’t get molars). Between eight and 12 weeks, baby teeth loosen, and permanent teeth start coming in (incisors, canines, premolars – in that order); all their adult teeth, including molars, should be in by about six to eight months. If you’re unsure, ask a vet or experienced shelter worker.  
  • Look at their paws. If paws are strongly built and look oversized, chances are it’s not going to be a tiny dog; delicate little paws will be more likely to belong to smaller dogs.
  • Skin test. Unless you have a Sharpei, lots of loose, baggy skin generally indicates that they still have plenty of growing to do.
  • Height and weight. At 14 to 16 weeks old, double their current height and weight for a general idea.
  • Boy or girl? Males tend to be larger than females.
  • Do a DNA test. By finding out what your puppy’s dominant breeds are, you’ll have a better idea of eventual size and weight.
  • Check out this handy calculation chart online:

None of the above is 100% accurate, but by adding it all up, you’ll have a better idea. Bear in mind that there may still be some surprises in store so, if your dog’s size is very important, it’s best to get a slightly older puppy – say, four to six months – as you will be able to predict more accurately. Choosing a dog, of any age, is a lifetime commitment, and having all the facts is crucial to help you make the right choice and be a true forever home.

Testimonial Story I

Our Duffel Bag Dog

Written by Yolandi Christiani

From ‘handbag dog’… … to ‘duffel bag dog’

I got Cola as a teeny-tiny foster puppy when he was about five weeks old. I immediately fell in love with him and his sister – at that stage it was purely because of their size. They looked like little Miniature Pinscher-mix lap doggies.

After a few weeks I decided I couldn’t let go of Cola and adopted him; everyone joked about my little ‘handbag dog’. He was predicted to be a small dog… As time went on, he started growing, first in his ears, then the legs, and the rest of his body eventually caught up. And he just kept on growing. Today, three years later, Cola weighs in at 32kg. My husband now affectionately calls him my ‘duffel bag dog’! And, although he’s rather bigger than predicted, I love him just as much as when he was my little ‘handbag dog’.

Testimonial Story II

Spoilt boy Rango

Written by Michelle Raath

Rango as a puppy… Rango today

Rango was rescued by CLAW from the township because he was being stoned. They took him to safety, and he went up for adoption; we were assured that he would be a small doggy, not much bigger than a Jack Russell… Well, he just grew and grew, and, today, he’s a gorgeous knee-height dog with a huge personality.

As the only male dog in the house he is rather spoilt by his dad – who denies it all. He is the most special dog ever and has brought so much joy and laughter to this family.