How big will my puppy get?
This puppy weight calculator estimates your puppy’s adult weight from three things you know today: its weight, its age and its expected size (or breed). Instead of a single rule of thumb, it uses growth curves for six size groups, worked out from the openly published data behind a 2017 veterinary study of almost a million purebred dogs, separately for females and males.
You get the most likely adult weight, the range that 8 in 10 similar puppies ended up in, how much of its adult weight your puppy has already reached, expected weights at six and twelve months, and a growth chart. Choose a breed and the tool also shows the breed standard for comparison.
It is an estimate built from averages — useful for planning a crate, a harness or a food budget, but not a promise. Your vet weighs your puppy at each visit and can tell you whether it is growing well.
How to use the Puppy Weight Calculator
- Enter your puppy’s weight today in kg or lb.
- Enter its age in weeks or months (from 8 weeks to 2 years).
- Choose the breed, or for a mixed breed pick the expected adult size.
- Choose female, male or not sure.
- Read the adult estimate and range, then look at the growth chart and the rules-of-thumb table below it.
Puppy Weight Calculator features
Size-specific growth curves
Six groups from toy (under 6.5 kg) to giant (40 kg and over), because small dogs finish growing months earlier than big ones.
Female and male curves
Females reach a slightly larger share of their adult weight at the same age, so sex is taken into account.
Honest range
The 10th–90th centile band shows how much puppies of the same size and age really vary.
Breed standard check
78 breeds with the weight ranges published by the American Kennel Club (Cane Corso from the FCI standard).
Animated growth chart
Projected curve, the range of similar puppies, the breed band and your puppy’s point today.
How the prediction works
Salt and colleagues (WALTHAM and University of Liverpool, PLoS ONE 2017) built growth standards from the records of over six million young dogs seen at US primary-care vet hospitals, and published the data under an open licence (CC BY 4.0). For this tool we took every dog in that data set with an adult weight recorded at 18 months to 3 years — 976,291 dogs — and, for each week of age, calculated what fraction of its own adult weight it weighed, using visits marked as preventive care or healthy and leaving out puppies recorded as thin or heavy.
Adult weight ≈ weight today ÷ typical fraction at this age. Example: a 10 kg medium-large puppy at 16 weeks. Puppies of that size weigh about 41% of their adult weight at 16 weeks, so the estimate is 10 ÷ 0.41 ≈ 24.4 kg; 8 in 10 such puppies finished between 19.3 and 31.5 kg.
Size groups and when growth slows
The study itself charted only groups up to 40 kg; the giant curve here comes from the same data but is less certain. “Adult” here means the weight recorded between 18 months and 3 years, so the last few per cent include filling out after growth in height has stopped.
| Size group (adult weight) | Example breeds | Share of adult weight at 16 weeks | Reaches 95% about |
|---|---|---|---|
| Toy (under 6.5 kg) | Chihuahua, Yorkshire Terrier, Pomeranian | 50% | 15 months |
| Small (6.5–9 kg) | Shih Tzu, Miniature Schnauzer, Dachshund | 50% | 14 months |
| Medium (9–15 kg) | Beagle, Pug, Cocker Spaniel | 44% | 16 months |
| Medium-large (15–30 kg) | Siberian Husky, Boxer, Border Collie | 41% | 13 months |
| Large (30–40 kg) | Labrador, Golden Retriever, German Shepherd | 40% | 15–16 months |
| Giant (40 kg and over) | Great Dane, Mastiff, Rottweiler | 35% | 16 months |
About the rules of thumb
You will often read “double the weight at 16 weeks” or “double the weight at six months”. The table under the chart shows what the data say for your size: for a large breed at 16 weeks the real multiplier is about 2.5, so doubling underestimates; for a toy breed at six months it is about 1.4, so doubling overestimates. These rules have no single published source, which is why this tool uses the data instead.
Puppy Weight Calculator FAQ
How accurate is a puppy weight calculator?
The shown range covers 8 in 10 puppies. At 16 weeks it runs from about 20% below to 30% above the estimate; at six months it narrows to roughly 17% below to 25% above; at 8 weeks it is much wider. Predictions get better as your puppy grows.
Does a female puppy need a different calculation?
Yes, slightly. At the same age a female has reached a little more of her adult weight than a male, so choosing female gives a slightly lower estimate for the same weight today.
How big will my Yorkie get?
Choose Yorkshire Terrier: it sets the toy curve and shows the standard (7 lb and under). Many pet Yorkies are heavier than the show standard and perfectly healthy.
My mixed-breed puppy — which size do I choose?
Use the parents’ weights if you know them, or your vet’s guess. If unsure, try two sizes and compare; paw size is not a reliable guide.
Should I feed more to reach the predicted weight?
No. Overfeeding large-breed puppies can harm their joints. Feed for a lean body condition — see the dog food calculator — and check with your vet.
Where can I see adult weights by breed?
The dog weight chart lists breed standard weights for males and females with a body condition check. For age in human years, try the dog age calculator.