When do puppies stop growing?
Short answer
Small breed puppies typically stop growing by 6 to 8 months, medium breeds at about 12 months, and giant breeds between 12 and 18 months, according to the American Kennel Club. Very large breeds such as Mastiffs may take up to 24 months. Enter your puppy’s size group and age below to see how much of its adult weight it has reached.
Key takeaways
- Small breeds typically stop growing by 6 to 8 months, medium breeds at about 12 months and giant breeds at 12 to 18 months.
- Very large breeds such as Mastiffs may not reach full size until 24 months.
- The AKC says bone development can take anywhere from 6 to 24 months.
- Large to giant breeds usually weigh 70 pounds or more as adults.
When does each size of puppy stop growing?
| Size | Typical age at full growth |
|---|---|
| Small breeds | By about 6 to 8 months |
| Medium breeds | Around 12 months |
| Giant breeds | 12 to 18 months |
| Very large breeds such as Mastiffs | Up to 24 months |
The AKC adds that bone development can take 6 to 24 months overall, and that large to giant breeds usually weigh 70 pounds or more as adults.
How grown is my puppy now?
The AKC also publishes the approximate share of adult weight puppies reach at each age. The calculator above reads this chart.
| Age | Small0 to 20 lb as an adult | Medium21 to 50 lb as an adult | Large51 to 100 lb as an adult | Extra-largeover 100 lb as an adult |
|---|---|---|---|---|
| 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% |
How do I estimate my puppy’s adult weight?
Use the adult weight estimator, which divides your puppy’s weight by the share in the chart. See the full puppy growth chart too.
Frequently asked questions
Do puppies stop growing at 6 months?
Only small breeds typically do, by about 6 to 8 months according to the AKC. Medium breeds reach adult size at around 12 months, and giant breeds at 12 to 18 months.
Is my 9-month-old large breed puppy still growing?
Probably. On the AKC chart a large puppy has reached about 75 percent of adult weight at 9 months and about 100 percent at 18 months.
How long do the biggest breeds keep growing?
Very large breeds such as Mastiffs may not reach full size until 24 months, the AKC says.
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