Free tool by Omelo
How big will your puppy get? Estimate the adult weight range from your puppy's age, current weight, and size class.
What size will
your puppy be?
Pick the adult frame that matches your puppy's breed or parents. This sets the growth curve.
How big will my puppy get?
To estimate how big a puppy will get, divide its current weight by the fraction of adult weight it should have reached at its age for its size class. For example, a small-breed puppy is near 50% of its adult weight at about 14 weeks, so a 3 kg puppy at that age would reach roughly 6 kg. Toy and small breeds usually finish growing around 10 to 12 months, large breeds around 12 to 18 months, and giant breeds around 18 to 24 months. This is an estimate. Breed, genetics, sex, and nutrition all shift the real adult weight.
The method: growth-percentage tables by size class
This predictor uses the percentage-of-adult-weight method that veterinary growth charts are built on, such as the WALTHAM Petcare Science Institute puppy growth charts. The idea is simple. At any age, a puppy has reached a known share of its final adult weight, and that share depends on how big the breed grows. The formula is: predicted adult weight = current weight divided by the fraction of adult weight already reached.
Bigger breeds grow for longer, so the same age maps to a smaller fraction of adult weight. A 16-week small-breed puppy is already past halfway, while a 16-week giant-breed puppy is closer to a third of the way there. That is why size class matters more than any single number. The specific per-age percentages in this tool are our own interpolation, anchored to the published consensus milestones above, so treat every result as an estimate rather than a fixed figure.
When do puppies stop growing?
Toy and small breeds: Fastest to finish. Most reach their adult weight by 10 to 12 months, and are already near half of it by 12 to 16 weeks.
Medium breeds: Usually done by 12 to 14 months, with the fastest gains in the first six months.
Large breeds: Keep filling out until about 12 to 18 months. They reach roughly half their adult weight around five to six months.
Giant breeds: The slowest to mature, often still growing at 18 to 24 months. Forced fast growth is a joint risk, so large and giant puppies should grow steadily, not quickly.
A note on kittens
This tool covers puppies. Kittens follow a different growth curve and most reach their adult size by around 10 to 12 months, so the size classes and percentages here do not apply to cats.
Frequently asked questions
How big will my puppy get?
To estimate a puppy's adult weight, divide its current weight by the fraction of adult weight it should have reached at its age for its size class. A small-breed puppy is near 50% of its adult weight at about 14 weeks, so a 3 kg small-breed puppy at 14 weeks would reach roughly 6 kg. This is an estimate. Breed, genetics, sex, and nutrition shift the real number.
What is the growth-percentage method?
The growth-percentage method uses published puppy growth charts that show what share of adult weight a puppy has reached at each age for its size class. You take the current weight and divide by that fraction. Because bigger breeds grow for longer, the same age maps to a smaller fraction of adult weight for a large or giant breed than for a toy or small breed.
When do puppies stop growing?
Growth timing depends on adult size. Toy and small breeds usually finish growing around 10 to 12 months. Medium breeds finish around 12 to 14 months. Large breeds keep growing until about 12 to 18 months, and giant breeds are not fully grown until 18 to 24 months, sometimes longer.
How accurate is a puppy adult weight prediction?
It is an estimate, not a guarantee. The prediction is most reliable after about 16 weeks and least reliable in very young puppies. Two puppies from the same litter can reach different adult weights. Use the predicted range as a planning guide for food, crate, and harness sizing, and confirm your puppy's growth with your vet.
Does breed or genetics change the result?
Yes. Breed, parent size, sex, spay or neuter timing, and nutrition all move the final adult weight. Mixed-breed puppies are the hardest to predict because the parents can carry different size genes. The size class you pick sets the growth curve, so choosing the class that matches your puppy's expected adult frame gives the closest estimate.
Why tracking growth matters
A single prediction is a starting point. What tells you far more is the shape of the curve over time. Steady weight gain that tracks the size class is a good sign. Sudden jumps, plateaus, or loss can flag a diet or health issue early. Omelo lets you log each weigh-in, see the growth curve build, and catch changes worth a vet visit. The predictor tells you where your puppy is headed. Omelo tells you if the trip is going to plan.