Puppy Weight Predictor
How big will your puppy get? Enter their current weight, age in months and expected size for an estimated adult weight.
A growth-curve estimate, most reliable from about 8 weeks on. Mixed breeds and the giant sizes vary the most — your vet or the parents' weights are the best guide.
Estimate only — not veterinary advice. Every animal is different; for a medication dose, a possible poisoning, or any emergency, call your veterinarian or an animal poison control line right away.
How the prediction works
Puppies don't grow in a straight line — they pile on weight fast in the first months, then taper as they near their adult size. This tool uses a growth curve for each size band to estimate what fraction of adult weight your puppy has reached at their current age, then divides to project the finished weight. Bigger breeds use a longer curve, because they keep growing well past a year.
Feeding a growing puppy
Aim for steady growth, not maximum growth. Feed a complete puppy (or all-life-stages) food, measure portions, and check body condition — you should be able to feel the ribs easily. For large and giant breeds especially, avoid overfeeding: growing too quickly stresses developing joints and is linked to orthopedic problems. When in doubt, your vet can confirm your puppy is on a healthy curve.
Frequently asked questions
- How big will my puppy get?
- The best simple predictor is how much they weigh now and how old they are, adjusted for expected adult size. This calculator uses growth curves: puppies grow fast early and slow as they approach adult weight, and bigger breeds keep growing for longer. Enter the current weight, age in months and expected size for an estimate.
- When is a puppy fully grown?
- It depends on size. Small breeds reach their adult weight by about 10–12 months; medium breeds around 12 months; large breeds 12–15 months; and giant breeds keep filling out until 18–24 months. That's why the same age means a different 'percent grown' for different sizes.
- How accurate is a puppy weight predictor?
- It's a good ballpark, especially from about 8 weeks of age onward, but not exact. Mixed breeds are the hardest to call. If you know the parents' weights, the puppy usually lands somewhere between them; for a mixed breed of unknown parentage, treat the estimate as a rough guide.
- My puppy seems too big or too small — should I worry?
- A single weight is just a snapshot. What matters more is a healthy body condition (you should be able to feel the ribs) and a steady growth curve. If your puppy seems very over- or under-weight, ask your vet — and don't overfeed a large-breed puppy, since growing too fast can harm their joints.
Sources
These are the references behind this calculator. Where a source gives a range we take the midpoint and round toward caution, and where we go beyond what a source states — an extra safety margin, or a rule of thumb rather than a clinical threshold — the page says so in the text above.
- Feeding growing puppies — VCA Animal Hospitals
- Global Nutrition Guidelines — WSAVA