DogsLifeFree tool
Puppy adult size estimator: how big will my puppy get?
Enter your puppy's age (6 to 18 months) and current weight. The estimator uses the American Kennel Club's growth chart, which says how much of its adult size a puppy has typically reached by each age, and works out a rough adult weight.
Puppies grow at very different speeds depending on their adult size. The American Kennel Club's growth chart gives the typical share of adult size reached at 6, 9, 12, 15 and 18 months for small, medium, large and extra-large dogs. The estimator divides your puppy's weight by that share, using the size class the result itself falls into.
The AKC growth chart
| Age | Small (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% |
The AKC says all its numbers are approximate. VCA Animal Hospitals give similar timing: small breeds usually reach adult size between 6 and 12 months, and most large breeds between 12 and 18 months.
Using the result
Adult size affects how long your puppy stays on puppy food, how much exercise suits it while it grows, and how much it will eat as an adult. See the puppy feeding schedule for when to switch food, and the dog calorie calculator once your dog is grown. For a purebred puppy, the kennel club weight on its breed page is a better guide than any formula.
Frequently asked questions
At what age is a puppy fully grown?
It depends on size. The AKC says small breeds usually stop growing by 6–8 months, medium breeds at about 12 months, and large and giant breeds at 12–18 months, with some giants still growing at 24 months.
How accurate is this?
Rough. The AKC calls its growth percentages approximate, and individual puppies vary. Treat the result as a ballpark and ask your vet, who can judge growth from body condition.
Why can't I enter a younger puppy?
The AKC chart starts at 6 months. Before that, growth varies so much between breeds and individuals that a percentage-based estimate would be misleading.
My puppy is a purebred. Is there a better guide?
Yes: the breed's standard adult weight. Our breed pages list kennel club weight and height ranges for 50 breeds.
Sources
- When do dogs stop growing? Puppy growth chart — American Kennel Club
- Puppy growth and maturity — VCA Animal Hospitals