How Big Will My Puppy Get?
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Start typing your dog's breed — we'll set the size group automatically. Or scroll down to pick manually.
Or select size group manually
How the prediction works
Different size groups grow at fundamentally different rates. A Labrador and a French Bulldog can weigh the same at 8 weeks and finish at vastly different adult sizes. That's why breed-specific growth curves give far more accurate results than generic formulas.
Growth rate by size group
| Size group | % grown at 4 mo | % grown at 6 mo | Full maturity |
|---|---|---|---|
| Toy (< 10 lbs) | ~55% | ~78% | 10–12 months |
| Small (10–25 lbs) | ~50% | ~74% | 10–12 months |
| Medium (25–50 lbs) | ~44% | ~68% | 12–15 months |
| Large (50–90 lbs) | ~37% | ~62% | 15–18 months |
| Giant (90+ lbs) | ~31% | ~54% | 18–24+ months |
Typical % of adult weight by size group, with maturity ages from veterinary references.
Toy and small breeds finish growing by about 10–12 months; medium breeds around 12–15 months; large breeds by 15–18 months; and giant breeds may keep filling out until 18–24 months, as their larger growth plates close later.
Why results are shown as a range
No calculator can guarantee an exact adult weight. Genetics, nutrition, health history, and individual variation all play a role. Even dogs from the same litter can end up 10–20% apart in adult weight. Showing a range is more honest — and more useful — than a false precision single number.
Puppy size & growth FAQs
1How accurate is a puppy weight prediction?
Predictions are most accurate after 12 weeks of age when reliable growth patterns have established. Before 8 weeks, birth weight variation from uterine placement means current weight isn't yet a strong predictor of adult size. The most accurate method is a DNA test from providers like Wisdom Panel, but breed-based growth curves give a solid estimate for purebreds and known crosses.
2How big will my puppy get?
Adult size depends primarily on breed and genetics. As a rule of thumb, most dogs reach about 75% of their adult weight by 6 months. Small breeds mature by 10–12 months, medium breeds by 12–15 months, large breeds by 15–18 months, and giant breeds may not finish growing until 24 months. Use the calculator above with your puppy's current age and weight for a breed-specific estimate.
3Can I predict a mixed breed puppy's adult size?
Yes, with lower confidence. Select the size group closest to what the mix is likely to produce. If you know both parents' sizes, averaging them gives a reasonable estimate. The prediction range will naturally be wider for unknown mixes. DNA testing is the most reliable option for mixed breeds.
4Do male puppies grow bigger than females?
Yes, across virtually all breeds adult males are 10–20% heavier than females of the same breed. This varies by breed — the gap is larger in some working and giant breeds, smaller in toy breeds. Select sex in the calculator to note this in your prediction.
5At what age is a dog fully grown?
It depends on size. Toy and small breeds (under 25 lbs) are typically full-grown by 10–12 months. Medium breeds reach adult size around 12–15 months. Large breeds like Labradors and German Shepherds finish growing at 15–18 months. Giant breeds like Great Danes and Mastiffs may continue filling out until 2 years or beyond.
6Does neutering affect adult size?
Research suggests neutering before roughly 9 months slightly increases adult size, while neutering after that age has little to no effect. The hormones involved in sexual maturity also signal growth plates to close, so early spay/neuter can allow slightly more growth. The effect is generally small — a few percent at most.
7Why is my puppy bigger or smaller than predicted?
Normal individual variation accounts for most differences. Even littermates can end up at quite different adult weights. Nutrition during puppyhood, health history, and genetics all contribute. A puppy that was the runt at birth can catch up significantly, and the biggest pup of the litter doesn't always become the largest adult.
8Can I tell how big my puppy will get by their paw size?
Paw size is a popular but unreliable predictor. While large paws at a young age can hint at a bigger adult, many small-breed puppies have proportionally large paws that they grow into quickly. Breed-specific growth curves based on current weight and age are far more accurate than paw size alone. DNA testing is the gold standard for mixed breeds.