How puppy growth works
Puppies grow fastest in their first few months, then taper off as they approach maturity. How long that takes depends mostly on size: small dogs finish early, while large and giant breeds keep growing well past their first birthday. The calculator works by estimating what fraction of their adult weight a puppy has already reached at its current age, then scaling up — which is why a realistic answer needs the size, not just the weight.
Puppy growth chart (% of adult weight)
| Age | Toy | Small | Medium | Large | Giant |
|---|---|---|---|---|---|
| 8 weeks | 30% | 26% | 22% | 18% | 15% |
| 3 months | 46% | 42% | 37% | 32% | 27% |
| 4 months | 58% | 53% | 49% | 43% | 37% |
| 6 months | 78% | 72% | 66% | 60% | 54% |
| 9 months | 95% | 90% | 85% | 78% | 72% |
| 12 months | 100% | 100% | 95% | 90% | 85% |
| 18 months | 100% | 100% | 100% | 100% | 95% |
Approximate — individual puppies vary by breed, sex, and genetics.
Not sure what size your puppy will be? Our breed guides list typical adult weights, and once they’re grown the feeding calculator helps you get portions right.
Frequently asked questions
How big will my puppy get?
Most puppies reach about half their adult weight by 4–6 months. Small breeds finish growing around 10–12 months, medium breeds around 12–14 months, and large or giant breeds keep filling out until 18–24 months. Enter your puppy’s age, weight, and expected size above for an estimate.
How accurate is a puppy weight calculator?
It’s a guide, not a guarantee. The estimate is based on typical growth curves for each size category, but genetics, breed, sex, and nutrition all cause variation — so treat it as a ballpark with a likely range. It’s most reliable from about 8 weeks of age. For a precise expectation, check the breed standard and ask your vet.
When is my puppy full grown?
It depends on size: toy and small breeds are usually full-grown by 10–12 months, medium breeds by about 12–14 months, large breeds by 15–18 months, and giant breeds not until 18–24 months. Big breeds gain height first, then fill out.
Can paw size predict how big a puppy will be?
Large paws can hint at a bigger frame to come, but they’re not a precise predictor. A puppy’s current age and weight combined with its breed’s size category gives a much better estimate than paws alone.