Puppy Weight Calculator
How big will your puppy get? Enter its weight, its age, and the expected adult size of its breed to estimate its adult weight and the range it will most likely fall in.
A rough estimate
Estimated adult weight
30 lb
Check the highlighted fields to see your result.
- Likely range
- 25.5–34.5 lb
- Grown so far
- 50%
- In the other unit
- 13.6 kg
Results are estimates for information only and do not constitute financial, medical, or legal advice.
How it works
Puppies grow quickly at first and then slow down. How much of its adult weight a puppy has reached at a given age depends on its size: small breeds finish growing earlier than large and giant ones. The calculator picks the typical share of adult weight for your puppy's age and size group, and divides the current weight by it. It shows a range of ±15%, because individual puppies grow differently.
The formula
Adult weight ≈ current weight ÷ share of adult weight reached at this age
For example, a medium-breed puppy is typically about half of its adult weight at 16 weeks, which is the familiar "double the weight at 4 months" rule of thumb. Small breeds are often about a third of their adult weight at 8 weeks.
Worked example
A medium-size puppy weighs 15 lb at 16 weeks.
- Share of adult weight at 16 weeks for a medium breed: about 0.50.
- Adult weight: 15 ÷ 0.50 = 30 lb.
- Likely range (±15%): 25.5 to 34.5 lb.
Sources and cautions
These are estimates based on size group, not on a particular breed. There is no universal formula; see theMerck Veterinary Manual on feeding and growthand the American Kennel Club's guide towhen puppies finish growing. Your veterinarian can track your puppy's growth on a chart and tell you if it is on a healthy path.
Frequently asked questions
How accurate is a puppy weight estimate?
It is only a rough guide. The Merck Veterinary Manual notes that there is little published data on growth curves by breed, and mixed-breed puppies are the hardest to predict. A DNA test, the size of the parents, and your vet's growth chart give a better picture.
When do dogs stop growing?
Small breeds usually reach adult size at about 12 months. Larger dogs may keep growing until 18 to 24 months, and some giant breeds fill out for even longer, according to the American Kennel Club.
Should I feed my large-breed puppy less to keep it small?
No. Do not restrict food to control size. Large-breed puppies need a growth formula and portions that keep them lean, because growing too fast can stress their joints. Ask your vet to set a feeding plan.