When Do Dogs Stop Growing?
Are you wondering when your puppy is fully grown? Or is your pup still getting bigger, even after a year at home?
When it comes to answering when do dogs stop growing, it’s important to check the science behind this question.
Knowing if your dog has stopped growing or not can help detect unknown health conditions that might go unnoticed!
Here’s what you should know about it.
Why Is It So Hard To Know When Is My Dog Fully Grown?
Dogs have amazing intra-species variability. This means that even if they are the same species, individuals can be very different from one another. Just look at a Chihuahua and a Saint Bernard! They are both dogs, but have pretty much nothing in common.
Plus, even if specific breeds have more or less a standard, there’s some wiggle room within that. Because of it, some pups might be even 30 kilos heavier than others, within the same breed!
If you’ve adopted a crossbreed or a mutt, it might be even more difficult to figure out if they’re fully grown. Mixed breed dogs have an unknown heritage, and sometimes they turn out completely different in size to both their parents.
However, having an idea of your dog’s fully grown size will be helpful to figure out their health. A dog that isn’t growing fast enough, or has stunted way below their ideal size, might also have other health issues including malnutrition or chronic conditions. In those cases, it’s best to know so you can take them to the vet ASAP!
When Do Puppies Stop Growing?
Growing depends on their bone structure
Whether or not your dog keeps growing will depend on their bone structure and skeletal growth. This means that once their bones stop growing, your pup won’t grow in size.
This is a natural process that can happen anywhere between 6 to 24 months old.
PRO TIP: If you want to know if your dog is fully grown, check for growth plates. These are softer bone areas in specific parts of the body where new growth happens. Once these are solid, your puppy won’t grow any more. You can feel some growth plates, but your vet can also do an x-ray.
Your puppy’s genes play a role
Of course, your puppy’s parents play a role in their final size. It’s easier to know if purebred puppies are done growing because they’ll be similar to their parents in size.
On the flip side, this is what makes crossbreed dogs harder to gauge. For adopted mixed breed puppies, it’s very hard to figure out their final size because you probably don’t know their parents.
PRO TIP: Puppies within the same litter can grow at different rates depending on their position within the litter and their weight at birth. No worries, most times even the smallest puppies will catch up to the rest once they eat regular puppy food. However, crossbreed pups might have littermates of slightly different sizes. 
Sexual hormones can affect how your puppy grows
Of course, hormones are important in your dog’s development. This is very important if you’re looking to spay or neuter your puppy.
Spaying and neutering is a healthy decision and will positively impact your dog’s life. However, ask your vet about the best time to do it. This will depend on your dog’s breed, age and health. Several studies have shown that too early spay/neuter can affect growth plates, delaying their “closure”.This delay causes dogs to become taller than they should be. On top of making your dog slightly larger, this can pose health risks since growth points might not calcify properly and become weak, or your dog could also suffer from joint issues due to heavier weight overall. 
PRO TIP: Discuss your spay/neuter schedule with your vet. In general, small or medium sized dogs should be between 6-10 months of age for their procedure. For large breed dogs that have a higher risk of joint disease, the recommendation varies on gender. For females, spaying should wait until after the first heat cycle, and for males, neutering can be scheduled when the dog is around two years old.
Nutrition is key
Dog malnutrition early on is life-threatening for puppies. Research shows that puppies that don’t eat enough are more prone to health issues and can fail to thrive .
This means breastfeeding is key from the first day. The weakest puppy in the litter tends to have a harder time latching on, and because of it, they grow slower than their littermates. Sometimes the difference is so stark that breeders need to supplement their nutrition. When puppies aren’t properly fed early on, their growth can stunt.
PRO TIP: Never wean a dog before 8 weeks of age. For larger breeds, some researchers propose extending breastfeeding time up to 12 weeks. Premature weaning can lead to stunted growth, but also improper solid food feeding and portioning when young can cause joint issues once your dog is an adult. Breastfeeding and small portions of solid food can help prevent these.
When Is A Dog Fully Grown? 3 Pro Tips
- Check their ribs. In the ribs you’ll find growth plates that are easy to feel. To do this, run your hands down your puppy’s rib cage. Carefully feel out ‘knobs’ in your dog’s ribs. If you can easily touch them, your pup will probably still grow taller. This trick works best for puppies between 6 and 10 weeks of age.
- Watch their teeth. In general, if your dog has already passed the teething process or is almost done, it’s a good sign they’re close to their final size. This one is great to figure out a crossbreed pup’s age and predict their growth. Ask a vet or people at your local shelter who will have the experience to figure out if your dog already has their adult teeth.
- Check their paws. This one is more anecdotal, but many shelters and rescue centres use this as a broad measure. Size up your dog from one to two metres afar. If they seem too ‘leggy’, or they have large paws for their overall frame, your pup will probably still grow taller.
At What Age Do Dogs Stop Growing?
If you’re wondering at what age do puppies stop growing, you should look at their breed and/or parents. The age a dog stops growing depends mainly on their predicted adult size. Large and giant dog breeds grow well beyond their first year, while smaller breeds mature faster . While this isn’t a strict rule, it can serve as a general guideline:
- Small and toy dog breeds: These are dogs whose expected adult weight is under 11 kilograms when fully grown. In general, small breeds reach their full size between 10 and 12 months of age. If your dog is a breed like Chihuahua, Mini Poodle, Bichon Frise or any other of that approximate size, this is probably their case.
- Medium dog breeds: These are pups that will weigh about 11- 23 kilograms when fully grown. Most medium size dogs double their first-week size between 8 - 12 weeks and generally, they’ll stop growing after the first year and up to 24 months. Medium-sized dogs are those similar to Beagles, Bulldogs, Staffies and Springer Spaniels.
- Large dog breeds: In this group, dogs will also double their born size at 8 - 12 weeks. After that, they’ll slowly put on size until they reach adult height and weight between 18 and 24 months. If you have a Golden Retriever, a Labrador, a German Shepherd or a Boxer, this is your pup.
- Giant dog breeds: These are dogs that will weigh between 50 and 110 kilograms as adults. In most cases, giant breed pups continue growing until they are around 30 months old!  This category includes dogs like Great Danes and Mastiffs, but also Great Pyrenees, Wolfhounds and others.
For those wondering ‘at what age do dogs stop growing’?, the short answer is, it depends. Based on your pup’s breed, feeding and genes, they’ll grow for a longer or shorter time. However, we can say that generally, larger and giant pups will take longer to grow to their adult size, while smaller puppies mature faster.
If you have more questions, ask your vet! They’ll have a better idea of your dog’s final size and will help you choose when to schedule their spay/neuter procedure.
Related: How Much Exercise Do Puppies Need?
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- Hart, B. et al. (2020). "Assisting Decision-Making on Age of Neutering for 35 Breeds of Dogs: Associated Joint Disorders, Cancers, and Urinary Incontinence". Frontier Veterinary Science, Volume 7, 2020. https://doi.org/10.3389/fvets.2020.00388
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