Dog Weight Calculator
Predict your puppy’s adult weight — enter its current weight and age and pick the breed size, and the calculator estimates how big it will grow.
Estimate only — not veterinary advice. It uses typical growth curves for small, medium and large breeds; an individual dog’s adult weight depends on its breed, genetics, sex, diet and health, so the real figure can differ. Ask your veterinarian about your puppy’s healthy growth and weight.
How to predict your puppy’s adult weight
A puppy reaches its adult weight gradually, and how fast depends on its breed size — small breeds mature much sooner than large ones. If you know roughly what fraction of its adult weight a puppy has reached at a given age, you can work backwards from its current weight to estimate the adult size. This calculator applies a typical growth curve for the breed size you choose.
adult weight ≈ current weight ÷ (% of adult weight reached at this age)
For example, a medium-breed puppy that weighs 10 lb at 16 weeks is typically about 42% of the way to its adult weight, which predicts roughly 24 lb grown. Pick the size band that matches your puppy’s expected adult size for the best estimate.
When is a dog fully grown?
| Breed size | Roughly full-grown by |
|---|---|
| Small (under 25 lb) | 9–12 months |
| Medium (25–55 lb) | 12–15 months |
| Large / giant (55 lb+) | 18–24 months |
This is an estimate from typical growth curves, not a guarantee — breed, genetics, sex and nutrition all shift the final weight, and mixed breeds are the hardest to predict. Always confirm a healthy target weight with your veterinarian.
Frequently asked questions
How can I predict my puppy’s adult weight?
Divide the puppy’s current weight by the share of its adult weight it has typically reached at its age, which depends on breed size — small breeds mature faster than large ones. The calculator applies a growth curve for the size you pick to estimate the adult weight from your puppy’s current weight and age.
At what age is a dog fully grown?
Small breeds usually reach their adult weight by about 9–12 months, medium breeds by 12–15 months, and large or giant breeds not until 18–24 months. That is why the same current weight predicts a different adult size depending on the breed category.
How accurate is a puppy weight predictor?
It is a rough estimate from typical growth curves, not a guarantee — breed, genetics, sex and nutrition all shift the final weight, and mixed breeds are hardest to predict. Use it as a guide and confirm a healthy target weight with your vet.