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Puppy Weight Predictor
How puppy growth works
Puppies grow along predictable S-curves. The key number is how much of adult size a puppy has already reached: a small-breed puppy sits near 50% of adult weight at 16 weeks, while a giant-breed puppy is only about 25% of the way there. Dividing current weight by that percentage gives the adult estimate, and between anchor points this tool interpolates linearly, which tracks published growth charts closely through the steep middle phase.
Expect the estimate to firm up with age. At 8 weeks the spread between size classes is wide; by 16 to 24 weeks it narrows a lot, and by 32 weeks most puppies are past 75% of adult weight. Mixed-breed puppies inherit curves from both parents, so treat the result as a range, not a promise. Sudden growth stalls or surges deserve a vet check.
Based on published size-classed puppy growth charts (Waltham / Royal Canin style curves). Individual puppies vary.
Related tools & guides
Frequently asked questions
How big will my puppy get?
Take current weight divided by the growth-chart percentage for its age and size class. Example: a 16-week small-breed puppy at 4 kg is ~50% grown, projecting to ~8 kg adult.
When do puppies stop growing?
Toy and small breeds finish around 8–10 months, medium by 12 months, large by 14–18 months and giant breeds can fill out until 18–24 months.
Is paw size a good predictor?
Loosely — big paws on a puppy usually mean a bigger adult, but the age-and-weight curve method is far more accurate.
Sources & methodology
- Growth percentages. Size-classed growth tables (fraction of adult weight at 8-72 weeks) approximating published Waltham- and Royal Canin-style puppy growth curves.
- Limits. Estimates carry roughly plus or minus 15%, widest at young ages; mixed breeds inherit curves from both parents. Growth stalls or surges deserve a vet check.
Last verified September 2026. Calculations on this page are implemented as unit-tested code. Estimates are educational, not veterinary advice. See our editorial policy.