When Do Dogs Stop Growing: Essential Guide for Adorable Pups

You’ve got a bouncy, clumsy puppy tearing through your house like a furry tornado. One day you’re wondering if they’ll ever stop getting bigger, and the next thing you know, they’re nearly full-size. But when do dogs stop growing? The answer isn’t one-size-fits-all—it depends on breed, genetics, and nutrition. As a vet tech who’s watched countless puppies transform into adult dogs, I can tell you that understanding your dog’s growth timeline is crucial for planning everything from nutrition to exercise to when you can finally trust them off-leash.

The short answer: most dogs stop growing between 12 and 18 months, but some large and giant breeds don’t finish until 2-3 years old. Small breeds often reach adult size by 10-12 months. But there’s way more to know about keeping your pup healthy during this critical phase.

Breed Size Matters Most

Here’s the reality: a Chihuahua and a Great Dane follow completely different growth schedules. Toy and small breeds finish growing fastest—sometimes by 10-12 months. Medium breeds typically reach full size by 12-15 months. Large breeds (think Labs, Golden Retrievers) keep growing until 18-24 months. Giant breeds (Mastiffs, German Shepherds, Great Danes) can grow until 24-36 months.

Why the difference? It’s all about bone development. Smaller dogs have less distance for growth plates to travel. Larger dogs need more time for their skeletal system to fully ossify—that’s the fancy term for bones hardening and fusing. The American Kennel Club recognizes breed-specific growth patterns, and understanding your dog’s breed standard helps you know what to expect.

I’ve seen owners shocked when their “almost adult” Lab suddenly shoots up another two inches at 20 months. It happens. A lot.

Growth Timeline by Breed

Toy Breeds (under 10 lbs): Chihuahuas, Pomeranians, Maltese. These little guys are basically done growing by 8-10 months. Their growth is fast but brief. By one year, they’re at or near full adult size. If you’re curious about coat changes in small breeds, check out our guide on do Pomeranian dogs shed—coat development continues even after size growth stops.

Small Breeds (10-25 lbs): Beagles, Cocker Spaniels, Shih Tzus. Growth continues steadily through 10-12 months. Most reach full height and length by one year, though they may fill out slightly after that.

Medium Breeds (25-50 lbs): Bulldogs, Collies, Springer Spaniels. These dogs grow for 12-15 months. Their growth is slower than toy breeds but faster than giants. They’re still building muscle and filling out their frame during this entire period.

Large Breeds (50-100 lbs): Labs, Golden Retrievers, German Shepherds. This is where patience matters. Growth continues for 18-24 months. Their bones are still developing, which is why jumping and rough play during growth can cause joint issues later.

Giant Breeds (over 100 lbs): Great Danes, Mastiffs, Saint Bernards. These gentle giants take the longest—sometimes 24-36 months to reach full maturity. Their growth plates close much later than smaller breeds, making them vulnerable to developmental orthopedic disease if exercised too hard too soon.

Pro Tip: If you don’t know your dog’s breed or mix, ask your vet to estimate their adult weight based on paw size and current growth rate. Bigger paws = bigger dog coming.

Nutrition During Growth Phases

This is where a lot of well-meaning owners mess up. During growth, your puppy’s nutritional needs are completely different from an adult dog’s. They need more calories, more protein, and the right balance of calcium and phosphorus for bone development.

Feed puppy-formula food until your dog reaches adult size—not just “until one year.” A large-breed puppy still growing at 18 months still needs puppy nutrition. Switching to adult food too early can stunt growth. Switching too late can cause obesity and joint stress.

The calcium-to-phosphorus ratio is critical, especially for large breeds. Too much calcium can actually interfere with bone development and increase the risk of hip dysplasia. This is why you shouldn’t just add supplements to your dog’s food without vet guidance. Quality commercial puppy foods are formulated correctly; homemade diets often aren’t.

Portion control matters, too. Overfeeding a growing dog—especially large breeds—accelerates growth, which stresses developing joints. It’s tempting to give your adorable puppy extra treats, but slow, steady growth is healthier than rapid growth.

PetMD’s puppy nutrition guide breaks down the specific nutrient requirements by breed size. Check it out if you’re feeding homemade or raw diets.

Exercise and Bone Development

Your puppy wants to play constantly. Your job is to limit it. I know that sounds counterintuitive, but here’s why: growth plates are soft cartilage until they fully ossify. Repetitive jumping, hard landings, and intense running can damage them before they’re ready.

A good rule of thumb: limit exercise to five minutes per month of age, twice a day. So a three-month-old puppy gets 15-minute sessions. A six-month-old gets 30-minute sessions. This isn’t about being overprotective—it’s about preventing injuries that don’t show up until your dog is five years old with arthritis.

Large and giant breeds are especially vulnerable. Their growth plates stay open longer, and their heavier bodies put more stress on developing joints. Avoid:

• Jumping on and off furniture
• Running on hard surfaces (concrete, asphalt) for long periods
• Repetitive fetch or ball-chasing
• Agility training before growth plates close
• Swimming for extended periods (though short swims are fine)

Soft surfaces like grass and dirt are gentler on developing bones. Swimming is actually excellent for growing dogs because it’s low-impact, but don’t overdo it.

Your puppy might seem frustrated by exercise limits. That’s okay. Mental stimulation (training, puzzle toys, sniffing games) burns energy without stressing joints. A tired brain is just as good as tired legs.

Signs Your Dog Has Stopped Growing

Growth isn’t always linear. Your puppy might grow quickly for a few months, then plateau, then grow again. So how do you know when when do dogs stop growing for real?

Physical signs:

• Paws are proportional to legs (no more clown-feet look)
• Head shape is fully developed
• Chest is deep and well-defined
• Muscle definition is visible
• No more visible growth spurts month-to-month

• Energy levels stabilize
• Appetite normalizes (they’re not constantly starving)
• Jumping and play-biting decrease naturally
• They’re calmer and more settled

Your vet can confirm by examining growth plates via X-rays, but honestly, most owners don’t need to do this. If your dog seems fully grown and has been stable in size for a couple months, they probably are.

One caveat: some dogs continue to fill out and gain muscle until age 3-4, even if their height stops changing. This is normal. They’re not growing taller; they’re maturing.

Common Growth Problems to Watch For

Not every puppy grows smoothly. Here are issues I see regularly in the clinic:

Developmental Orthopedic Disease (DOD): This umbrella term covers hip dysplasia, elbow dysplasia, and other joint issues that develop during growth. They’re partly genetic and partly environmental. Overexercise, poor nutrition, and rapid growth increase risk. Large and giant breeds are most vulnerable. The Orthopedic Foundation for Animals (OFA) provides screening and certification for breeding dogs.

Nutritional imbalances: Too much or too little calcium, vitamin D deficiency, or protein deficiency can cause soft bones, stunted growth, or joint problems. This is why puppy-formula food matters.

Panosteitis (“growing pains”): Young dogs, especially large breeds, sometimes develop inflammation in the long bones. They’ll limp or seem sore for a few days or weeks, then recover. It’s usually self-limiting but worth mentioning to your vet.

Retained baby teeth: Sometimes puppy teeth don’t fall out when adult teeth come in. If your dog still has baby teeth at 6-7 months, mention it to your vet. They might need extraction.

Uneven growth: Occasionally, one leg grows faster than others, causing temporary limping. This usually corrects itself, but mention it to your vet if it persists.

The best prevention? Quality puppy food, appropriate exercise limits, and regular vet checkups. Sounds simple because it is.

Spaying and Neutering Timing

This is a hot topic, and opinions vary. Traditionally, vets recommended spaying/neutering at 6 months. Now, research suggests waiting until after growth plates close might reduce certain joint problems, especially in large breeds.

Here’s the complexity: early spaying/neutering prevents reproductive cancers and unwanted litters. Late spaying/neutering might reduce orthopedic issues but increases mammary cancer risk in females. It’s a trade-off.

Current recommendations from the American Animal Hospital Association (AAHA) suggest discussing timing with your vet based on your dog’s breed, size, and health history. For large breeds, waiting until 12-24 months is increasingly recommended. For small breeds, 6 months is still reasonable.

Don’t delay indefinitely, though. The longer you wait, the higher the cancer risk in females. Work with your vet to find the sweet spot for your dog.

One more thing: when do dogs stop growing mentally? Behavior-wise, large breeds don’t fully mature until 2-3 years old. That bouncy, silly adolescent phase lasts longer than you’d think. Patience.

Frequently Asked Questions

Will my puppy’s paws tell me how big they’ll get?

– Partially. Oversized paws relative to legs suggest more growth is coming, but it’s not a perfect predictor. Genetics, nutrition, and breed mix all play a role. Your vet’s estimate based on current weight and growth rate is more accurate than paw size alone.

Can I tell if my puppy will be large or small by looking at the parents?

– Yes, usually. Puppy size at 8 weeks correlates fairly well with adult size if parents are known. Mixed breeds are trickier. If you adopted from a shelter, ask staff about the parents’ size if possible, or ask your vet to estimate.

Is it bad if my puppy grows too fast?

– Yes. Rapid growth, especially in large breeds, increases joint stress and developmental disease risk. This is why overfeeding and too much exercise are problems. Slow, steady growth is ideal.

My puppy seems to have stopped growing, but they’re smaller than the breed standard. Is something wrong?

– Not necessarily. Some dogs are naturally smaller than average for their breed. If your puppy is healthy, eating well, and acting normal, size variation is fine. Discuss with your vet if you’re concerned about stunted growth.

Can I switch to adult food before my dog stops growing?

– Not recommended. Puppy formula has the right nutrient balance for growing bones. Switching early can interfere with proper development. Wait until your vet says your dog is at full adult size.

Why do large-breed puppies need different food than small breeds?

– Large breeds grow for much longer and their bones are under more stress. Puppy food for large breeds has lower calcium and phosphorus to prevent over-mineralization, which can cause joint problems. It’s not just about quantity; it’s about the specific nutrient profile.

Is it normal for puppies to limp during growth?

– Occasional limping during growth spurts can be normal (panosteitis), but persistent limping isn’t. Mention it to your vet. It could be panosteitis, an injury, or something else that needs attention.

How do I know if my dog will have hip dysplasia?

– You can’t know for sure until they’re older, but genetic predisposition is real. Large breeds from good breeders should have parents screened via OFA or PennHIP. Proper nutrition and exercise during growth reduce environmental risk factors. If you’re curious about behavioral traits or health predispositions, check out our what type of dog are you quiz for fun insights.

Do male and female puppies grow at different rates?

– Slightly. Males tend to be larger at maturity, but the growth timeline is similar. Spaying/neutering can affect growth plate closure timing slightly, which is one reason vets now discuss timing with owners.

My dog is 2 years old and still seems to be growing. Is that normal?

– For giant breeds, yes. Some don’t fully mature until 3 years. For smaller breeds, growth should have stopped by 18 months. If your medium or small breed is still growing noticeably at 2 years, mention it to your vet—could be a thyroid issue or other metabolic problem.

Does neutering or spaying affect growth?

– Slightly. Early spaying/neutering can extend the growth phase slightly because it removes hormones that trigger growth plate closure. This might lead to slightly taller dogs with longer legs. Whether this is good or bad depends on your dog’s breed and individual risk factors.