When Do Puppies Stop Growing? Timeline by Breed Size
Published by MaunaPet. Editorial policy and sources.
Small dogs finish growing much earlier than large ones. Toy and small breeds are usually fully grown at 9–12 months, medium breeds at 12–14 months, large breeds at 15–18 months, and giant breeds can keep growing until 18–24 months.
Growth timeline by breed size
| Breed size | Adult weight | Half of adult size | Fully grown |
|---|---|---|---|
| Toy (Chihuahua, Yorkie) | Under 5 kg (11 lb) | 10–12 weeks | 9–10 months |
| Small (French Bulldog, Pug) | 5–10 kg (11–22 lb) | 12–14 weeks | 10–12 months |
| Medium (Beagle, Border Collie) | 10–25 kg (22–55 lb) | 16 weeks | 12–14 months |
| Large (Labrador, German Shepherd) | 25–45 kg (55–100 lb) | 20–22 weeks | 15–18 months |
| Giant (Great Dane, Mastiff) | Over 45 kg (100 lb) | 24–26 weeks | 18–24 months |
How grown is my puppy right now?
The American Kennel Club publishes approximate percentages of adult size by age:
| Age | Small (up to 20 lb) | Medium (21–50 lb) | Large (51–100 lb) | Extra large (100+ lb) |
|---|---|---|---|---|
| 6 months | 75% | 66% | 60% | 50% |
| 9 months | 90% | 85% | 75% | 65% |
| 12 months | 100% | 95% | 85% | 80% |
| 15 months | 100% | 100% | 95% | 90% |
| 18 months | 100% | 100% | 100% | 100% |
All numbers are approximate. Giant breeds often keep filling out with muscle after 18 months.
Height stops first, then the body fills out
Puppies grow taller while the growth plates near the ends of the long bones are still open. Once the plates close, height is set, but the chest broadens and muscle keeps developing for several more months. That is why a one-year-old large-breed dog can look lanky and still gain weight healthily.
What this means for feeding
- Feed a growth diet until your puppy is close to adult size. Large and giant breeds do best on food formulated for large-breed puppies.
- Do not push fast growth. Overfeeding does not make a dog bigger; it makes a puppy heavier on a skeleton that is still forming.
- Recalculate portions as your puppy grows. The dog calorie calculator uses 3.0 × RER under 4 months and 2.0 × RER from 4 to 12 months. See how many calories should my dog eat.
What this means for exercise
Until the growth plates close, keep exercise low-impact: avoid repeated jumping and hard agility work, and build up walks gradually. Ask your vet when your dog's breed is ready for strenuous sport, and about the best timing for neutering, which can differ for large breeds.
When to check with your vet
Book a visit if your puppy stops gaining weight for several weeks before the expected adult age, limps, has swollen joints, or is clearly smaller or thinner than littermates. For the stages in between, read puppy growth stages and weight chart.
Frequently asked questions
At what age is a puppy fully grown?
It depends on size. Toy and small breeds are usually fully grown at 9–12 months, medium breeds at 12–14 months, large breeds at 15–18 months and giant breeds at 18–24 months.
When do large breed puppies stop growing?
Large breeds such as Labradors and German Shepherds usually reach adult size at 15–18 months. Giant breeds such as Great Danes can keep growing and filling out until 18–24 months.
Is a 1-year-old dog still a puppy?
Small and medium dogs are close to adult size at 12 months. Large dogs are about 85% grown at 12 months and extra-large dogs about 80%, by the American Kennel Club's approximate chart, so they still have growing to do.
How can I tell how big my puppy will get?
Breed and the parents' size are the best guides. As a rough rule, medium breeds reach about half their adult size at 16 weeks and large breeds at 20–22 weeks. A puppy weight calculator gives an estimate from current age and weight.
Sources and further reading
- American Kennel Club — When Do Dogs Stop Growing?
- Merck Veterinary Manual — Puppy Care
- WSAVA — Global Nutrition Guidelines
Links checked on November 12, 2026. These sources support the topic; they do not certify this entire article. Consult your veterinarian for diagnosis and treatment.