When Do Large Breed Puppies Stop Growing? Month-by-Month

Your large breed puppy is already taking up half the couch at four months old — and the question of when this dog will actually stop growing is a fair one. The honest answer is that it depends on whether you have a large breed dog or a giant breed dog, and understanding the difference matters more than most owners realize.

Most large breed puppies (those that will weigh 50–90 lbs as adults) stop growing between 14 and 18 months of age. Giant breeds — those over 90 lbs — can keep growing until they're 20 to 24 months old. But here's what catches owners off guard: your puppy will look nearly full-grown long before they actually are. Use our puppy weight calculator to see exactly where your dog falls on the growth curve right now.

Large breed vs. giant breed: what the data actually shows

Most articles lump "large and giant breeds" together as if they grow on the same schedule. They don't. Based on veterinary growth data from Salt et al. (2017) — a PLOS ONE study analyzing over 8 million vet-measured weight records — the difference between large and giant breed growth timelines is substantial.

For large breed dogs (adult weight 50–90 lbs), our data shows:

• Large breeds reach 99% of adult weight around 70 weeks (about 16 months)
• Growth curves reach 100% completion by 72 weeks for most large breeds
• Males complete the curve slightly faster than females but the difference is just a week or two

For giant breed dogs (adult weight over 90 lbs), the timeline is much longer:

• Males reach 99% of adult weight around 100 weeks (about 23 months)
• Females reach 99% of adult weight around 100 weeks as well
• Growth is considered biologically complete by 104 weeks (2 full years) for many giant breeds

These aren't estimates. They're modeled from real vet measurement data. You can see how our growth predictions work if you want to dig into the methodology.

Growth by age: what to expect at each stage

One thing that surprises most new owners is how much growth happens in the first six months — and how little they know about what percentage of their dog's final size they're actually looking at. Here's a breakdown using exact figures from our analysis of veterinary growth records. For the full developmental picture at each milestone, see our week-by-week puppy growth stages guide.

8 weeks (when most puppies come home)

At 8 weeks old, a large breed puppy has reached just 16.2% of their adult weight (males) or 17.5% (females). For a dog that will eventually weigh 75 lbs, that's roughly 12–13 lbs. Giant breed puppies are even further behind — only 12.4% (males) or 13.5% (females) of their adult weight at this stage.

3 months (12 weeks)

Growth is rapid during this phase. Large breed puppies hit 27.9% of adult weight by 12 weeks. Giant breeds are at about 22.9%. Both are growing at their fastest pace right now. Enjoy the compact version while it lasts.

6 months (24 weeks)

This is where owners often think growth is nearly done. It isn't. At 6 months, a large breed puppy is at roughly 65.7% of their adult weight. Giant breeds are at about 59.0%. That means at the six-month mark, your large breed puppy still has more than a third of their total growth ahead of them.

9 months (36 weeks)

Large breeds are now at 87.8% of adult weight. Giant breeds are at 82.2%. Your puppy looks nearly adult-sized at this point, which is why so many owners assume growth is done. But the bones are still developing, and the growth plates haven't closed.

12 months (52 weeks)

At one year old, large breeds have reached 96.0% of adult weight (males) or 95.9% (females). Most of the height gain is done, but muscle development and body mass continue. Giant breeds at 12 months are only at 93.7% — still about 6% of their full size left to go, which on a 150-lb dog is close to 10 lbs.

Growth windows for popular large and giant breeds

Different breeds within the large and giant categories vary considerably. Here's what our breed dataset shows for some of the most popular large and giant breeds:

Breed	Category	Adult Weight (Male)	Adult Weight (Female)	Growth Window
Labrador Retriever	Large	65–80 lbs	55–70 lbs	~65 weeks
Golden Retriever	Large	65–75 lbs	55–65 lbs	~65 weeks
German Shepherd	Large	65–90 lbs	50–70 lbs	~72 weeks
Rottweiler	Large	95–135 lbs	80–100 lbs	~78 weeks
Doberman Pinscher	Large	75–100 lbs	60–90 lbs	~72 weeks
Boxer	Large	65–80 lbs	50–65 lbs	~65 weeks
Great Dane	Giant	140–175 lbs	110–140 lbs	~104 weeks
Bernese Mountain Dog	Giant	80–115 lbs	70–95 lbs	~90 weeks
Newfoundland	Giant	130–150 lbs	100–120 lbs	~104 weeks
Saint Bernard	Giant	140–180 lbs	120–140 lbs	~104 weeks

Notice that even within the "large" category, Rottweilers grow for about 78 weeks while Boxers and Labs tend to finish around 65. Heavier breeds within a size class typically take longer. Want to know your specific breed's timeline? Check your puppy's growth curve here.

Why growth plates matter more in large breeds

You'll hear a lot about growth plates when researching large breed puppy care. Here's what you actually need to know and why it matters for day-to-day decisions.

Growth plates are areas of soft cartilage near the ends of the long bones. They're what allow your puppy's skeleton to grow, and they harden — or "close" — once growth is complete. Until they close, they're softer and more vulnerable than mature bone. A high-impact injury to an open growth plate can cause uneven bone development or permanent joint damage.

In large breed dogs, growth plates typically close between 14 and 20 months. In giant breeds, closure can happen as late as 22 months. Compare that to small breeds, whose plates may close as early as 6 to 8 months. The longer your dog is growing, the longer that risk window stays open.

This is why exercise guidelines for large breed puppies are more conservative than for small breeds. It's not overprotection — it's just acknowledging that large breed bones take longer to mature.

How sex affects growth in large breeds

Most growth guides treat all large breed puppies as one uniform group. But our veterinary data shows a consistent difference by sex that's worth understanding.

Male large breed puppies tend to grow for slightly longer than females and reach a higher final weight. Looking at the growth curves from Salt et al. (2017):

• Large breed males reach full growth around 64 weeks
• Large breed females reach full growth around 66 weeks — females actually reach the same milestone a bit later but at a lower overall weight
• At 52 weeks (12 months), males are at 96.0% of their adult weight and females at 95.9% — nearly identical at this age

In practice, the sex difference in growth timeline is modest — we're talking about a few weeks. The bigger difference is in final size: a male Labrador typically weighs 65–80 lbs fully grown, while a female Lab weighs 55–70 lbs. Same breed, meaningfully different adult weights.

What affects how fast a large breed puppy grows

Genetics

Breed sets the fundamental template. Your puppy's adult size is mostly determined before they're born. For purebred large breed dogs, you can look at the parents for a reasonable estimate of adult size. For mixed breeds, the math gets trickier — our guide to predicting mixed breed adult size covers the most reliable methods, or you can run our calculator to estimate adult size from current weight and age.

Nutrition — and the problem with growing too fast

Here's a counterintuitive fact: for large breed puppies, growing too fast is a bigger concern than growing too slowly. Rapid early growth puts excess mechanical stress on developing joints and bones and is strongly associated with orthopedic problems like hip dysplasia and osteochondrosis.

Large breed puppy foods control growth rate by limiting calorie density and keeping calcium-to-phosphorus ratios in a specific range. This isn't a marketing gimmick — it's a documented veterinary recommendation. Our guide to large breed puppy food vs. regular puppy food breaks down exactly what's different and why it matters. Don't add extra calcium supplements unless your vet explicitly prescribes them. More calcium during puppyhood in large breeds can actually worsen bone development.

Spay and neuter timing

This is an area where veterinary recommendations have shifted significantly. Studies now show that early spay/neuter (before 6–12 months) in large and giant breed dogs delays growth plate closure, causing longer bones and altered body proportions — and raising the risk of joint problems like cruciate ligament tears and hip dysplasia. Our deep dive on how spaying affects puppy growth covers the data behind optimal timing by breed size.

Current guidance for large breeds generally recommends waiting until at least 12–18 months to spay or neuter. For giant breeds like Great Danes and Saint Bernards, some vets recommend waiting until 24 months. Talk to your vet about the right timing for your specific dog.

Health and parasite load

Intestinal parasites are common in puppies and can meaningfully slow growth by competing for nutrients. Regular deworming and fecal testing during the first year helps ensure your puppy's growth isn't being held back by a hidden parasite load. If your large breed puppy seems to be falling behind on weight gain, it's worth asking your vet about this before assuming the puppy just runs small.

Signs your large breed puppy is done growing

Here are the practical signs to watch for:

Weight has been stable for 4–6 weeks. If you're tracking monthly weights (which is a good idea), a plateau across multiple weigh-ins is the clearest signal. A pound or two of normal fluctuation is fine — a consistent plateau is meaningful.

Paws look proportional. Puppy paws are famously oversized relative to the body. As they grow into their frame, those paws start to look like they actually fit.

They're gaining breadth, not height. Once height gain stops, your dog may still be broadening through the chest and filling out with muscle. That's the final stage before growth truly ends.

A vet confirms growth plates have closed. This is the definitive test. X-rays of the wrist or knee joints can show whether the growth plates have hardened. If you're managing a dog with exercise restrictions due to growth concerns, this is the test that gives you permission to transition to an adult exercise routine.

Supporting healthy growth in large breed puppies

Feed a large breed puppy formula

Choose a food specifically labeled for large breed puppies, not just "puppy food." These formulas are lower in calories per cup and have balanced calcium-to-phosphorus ratios that prevent the accelerated growth associated with orthopedic problems. For specific portion guidance, see our feeding chart by expected adult weight. Follow the feeding guide on the bag and adjust based on your vet's body condition scoring — you should be able to feel the ribs with moderate pressure, but not see them.

Follow the 5-minute rule for exercise

A widely cited guideline for structured exercise is 5 minutes per month of age, up to twice per day. A 4-month-old large breed puppy gets about 20 minutes of leash walking per session. Free play in the yard — where your puppy self-regulates intensity — is generally fine beyond those limits. The concern is repetitive, forced, or high-impact exercise: long runs, jumping from heights, or sustained stair climbing before growth plates close.

Track weight monthly

Weighing your large breed puppy monthly and plotting it against a growth curve is one of the best things you can do. It catches both underweight and overweight trends early, before they compound into bigger problems. For specific numbers on what to expect each week, see our guide to how much weight a puppy should gain per week. Our free puppy weight calculator generates a breed-specific growth curve and tells you where your puppy sits on that curve right now.

Don't rush the vet timeline

Most large breed puppies need checkups at 8 weeks, 12 weeks, 16 weeks, and 6 months — then annually. These are also good opportunities to ask about body condition scoring, growth plate status as your puppy ages, and to refine your spay/neuter timing decision.

When do large breed puppies stop growing? FAQ

When do large breed puppies stop growing?

Most large breed dogs finish growing between 14 and 18 months. Based on veterinary growth data from Salt et al. (2017), large breeds reach 99% of adult weight around 70 weeks (16 months) and 100% by about 72 weeks.

When do giant breed puppies stop growing?

Giant breeds like Great Danes, Saint Bernards, and Newfoundlands take much longer. Our data shows giant breeds don't reach 99% of adult weight until around 100 weeks — about 23 months. Some very heavy giants don't look fully mature until closer to 24 months or beyond.

When do Labrador Retrievers stop growing?

Labs reach full height by about 12 months and finish filling out by 14 to 15 months. Male Labs weigh 65–80 lbs as adults and females weigh 55–70 lbs. Labs are on the faster end of large breed growth, finishing around 65 weeks in our dataset.

When do German Shepherds stop growing?

German Shepherds typically reach adult height around 12 months but continue building muscle and mass until 18 months or so. Males weigh 65–90 lbs and females 50–70 lbs. Their growth window runs to about 72 weeks, a bit longer than Labs and Goldens.

How do I know if my large breed puppy is done growing?

The clearest indicator is stable weight over several consecutive monthly weigh-ins. Other signs include proportional paws, a filled-out chest, and consistent body condition. Your vet can confirm by X-raying the growth plates — once they've closed, your dog is done growing.

Does spaying or neutering affect how long a large breed puppy grows?

Yes. Early spay or neuter before 12 months can delay growth plate closure in large breed dogs, leading to longer limbs and altered proportions — and a higher risk of joint problems. Current recommendations for large breeds generally favor waiting until 12–18 months, and up to 24 months for giant breeds. Discuss timing with your vet.