How the prediction works
Puppies grow along fairly predictable curves, and by a given age they’ve usually reached a known share of their adult weight. Because bigger breeds grow for longer, that share depends on size. The calculator divides your puppy’s current weight by the typical percentage for its age and size to estimate the adult weight, then shows a likely range around it.
When do dogs stop growing?
- Small breeds: around 9–12 months
- Medium breeds: around 12 months
- Large breeds: 12–18 months
- Giant breeds: 18–24 months
Frequently asked questions
- How big will my puppy get?
- A good estimate comes from how much of its adult weight a puppy has typically reached by its current age — which depends on size, since larger breeds grow for longer. Adult weight ≈ current weight ÷ that percentage. This calculator does the maths and gives a likely range.
- At what age is a puppy half its adult weight?
- Roughly: small breeds reach about half their adult weight by ~3.5 months, medium breeds by ~4–4.5 months, and large/giant breeds a little later. Small dogs finish growing around 9–12 months, while giant breeds can keep growing until 18–24 months.
- How accurate is a puppy weight predictor?
- Treat it as an estimate. It’s most reliable after about 12–16 weeks, and least reliable for mixed breeds where adult size is uncertain. Bone structure, the size of the parents, and individual variation all play a role.
- When do puppies stop growing?
- Small breeds are usually done by 9–12 months, medium breeds around 12 months, large breeds by 12–18 months, and giant breeds not until 18–24 months. Height tends to finish before they fill out in weight and muscle.
An estimate from typical growth curves — mixed breeds and individual puppies vary. For a tailored projection, your vet can assess your puppy’s frame, parents, and growth so far.