Puppy Weight Calculator
Enter your puppy’s age and weight to see a likely adult weight range, a growth curve, and when they’ll be full grown.
Most puppies reach half their adult weight between about 11 weeks (toy breeds) and 23 weeks (giant breeds). Small dogs finish growing by 8–12 months, while large breeds can take up to 24 months. Our calculator uses size-specific growth curves, so it’s more reliable than simply doubling a 16-week weight.
Puppy growth chart by size
How fast a puppy grows depends mostly on how big it will be. Toy breeds race to adult size; giant breeds take more than twice as long. These are the milestones our calculator uses:
| Size | Adult weight | Half grown | Full grown |
|---|---|---|---|
| Toy | under 12 lb | 11 weeks | ~9 months |
| Smallinterpolated | 12–24 lb | 12.5 weeks | ~9 months |
| Mediuminterpolated | 24–57 lb | 15 weeks | ~9.9 months |
| Largeinterpolated | 57–99 lb | 18 weeks | ~12.9 months |
| Giant | 99 lb and up | 23 weeks | ~15 months |
How we predict your puppy’s adult weight
Puppies follow an S-shaped growth curve: slow at first, fastest in the middle months, then leveling off. We describe that curve for each of five size groups with a standard logistic model. If a curve says a puppy of that size should be at 38% of adult weight at 12 weeks, and your puppy weighs 10 lb, the predicted adult weight is 10 ÷ 0.38, or about 26 lb.
The curves are anchored on published growth milestones. A study of 12 breeds found that small breeds such as the Papillon reach half their adult weight at about 11 weeks, while the English Mastiff takes about 23 weeks. Growth standard charts from WALTHAM and Banfield, built from healthy dogs at ideal body condition, show small dogs maturing between 8 and 12 months and larger breeds taking up to 24 months. Those charts don’t cover adult dogs over 40 kg, so our giant curve is an extrapolation.
We show a range of ±15% around the estimate. That band is our own choice, not a published figure, and reflects the normal variation between puppies of the same size.
When do puppies stop growing?
According to the AKC, small breeds usually stop growing by 6 to 8 months, and medium breeds reach their adult size at around 12 months. Giant breeds keep growing until 12 to 18 months, and very large breeds such as Mastiffs may not be fully grown until 24 months.
Growth happens at the growth plates near the ends of the long bones in the legs. Veterinarians quoted by PetMD say most dogs’ growth plates close at around 9 to 11 months, although large breeds can take longer. Until then, feed a puppy food made for your dog’s expected size.
Does the “double at 16 weeks” rule work?
The idea is simple: weigh your puppy at 16 weeks and double it. It is a rule of thumb, and we found no published study that validates it. Our growth curves show why it only works for some dogs. At 16 weeks a medium puppy is close to half its adult weight, so doubling lands near the mark. A toy puppy is already well past half, so doubling overshoots, and a giant puppy is only about a third of the way there, so doubling badly undershoots.
Another common shortcut divides weight by age in weeks and multiplies by 52. We show both rules next to our estimate in the results, and hide the weekly rule for large and giant breeds, where it doesn’t hold up.
How big will my mixed-breed puppy get?
If you don’t know what size your puppy will be, choose Not sure. The calculator first estimates with the medium-dog curve, then switches to the size group that estimate falls in and calculates again. If the result still lands in a different group, it tells you which size your puppy is tracking.
The best clues for a mixed breed are the parents. If you can find out their weights, the adult size usually falls somewhere around them. Your vet can also judge whether your puppy is growing at a healthy rate by scoring its body condition.
Can paw size predict adult size?
It’s a popular belief that big paws mean a big dog. Veterinarians quoted by PetMD say a puppy’s paw and ear size are not reliable indicators. Knowing the breed, or better still the parents, tells you far more.
How much should my puppy weigh at 12 weeks?
Using the same growth curves, here is the weight range you would expect at 12 weeks for each adult size. Treat it as a rough guide; healthy puppies vary.
| Adult size | Adult weight | Weight at 12 weeks |
|---|---|---|
| Toy | under 12 lb | under 6.6 lb |
| Small | 12–24 lb | 5.8–12 lb |
| Medium | 24–57 lb | 9.2–22 lb |
| Large | 57–99 lb | 19–32 lb |
| Giant | 99 lb and up | over 23 lb |
Frequently asked questions
How accurate is a puppy weight calculator?
It gives a reasonable range, not a guarantee. Our calculator uses growth curves for five size groups, anchored on published puppy growth studies, and shows a ±15% range around the estimate. Genetics, diet and health all shift where an individual puppy ends up.
At what age is a puppy half grown?
It depends on size. In our model, toy breeds reach half their adult weight at about 11 weeks, medium dogs at about 15 weeks and giant breeds at about 23 weeks. The toy and giant figures come from a study of puppies of 12 breeds.
Does doubling a puppy’s weight at 16 weeks work?
Only roughly, and mostly for medium-sized dogs. It is a rule of thumb, and we found no published study that validates it. By our growth curves, it overestimates toy breeds, which are past half their adult weight by 16 weeks, and underestimates giant breeds, which are well short of it.
How big will my mixed-breed puppy get?
Choose “Not sure” for adult size. The calculator first estimates with a medium-dog curve, then switches to the size group that estimate falls in and calculates again. If you know the parents’ weights, they are often a better guide than any formula.
Can paw size predict how big a puppy gets?
Not reliably. Veterinarians quoted by PetMD say the size of a puppy’s paws or ears is not a reliable indicator. Knowing the breed, or better still the parents, is more useful.
When do puppies stop growing?
Small breeds usually stop growing by 6 to 8 months and medium breeds at around 12 months, according to the AKC. Giant breeds grow until 12 to 18 months, and very large breeds like Mastiffs may take up to 24 months.
Are male puppies bigger than females?
In many breeds, yes. AKC breed standards often give males a higher weight range; for example, male Golden Retrievers are listed at 65–75 lb and females at 55–65 lb. Choose your puppy’s breed and sex in the calculator to see the standard.
How much should my puppy weigh at 12 weeks?
It depends on the adult size. Use the 12-week table on this page as a rough guide, or enter your puppy’s weight above to see which size group it is tracking.
Keep going
Sources
- Hawthorne A.J. et al. Body-Weight Changes during Growth in Puppies of Different Breeds. The Journal of Nutrition, 2004.
- Salt C. et al. Growth standard charts for monitoring bodyweight in dogs of different sizes. PLOS ONE, 2017.
- American Kennel Club. When Do Dogs Stop Growing?
- PetMD. Growth in Dogs: What to Expect.
- Montoya M. et al. Life Expectancy Tables for Dogs and Cats Derived from Clinical Data. Frontiers in Veterinary Science, 2023.
Estimates only — not a substitute for veterinary advice. Read our disclaimer.