How big will your puppy get?
A vet-built estimate from breed, age and weight, fitted to 440,000 real puppies.
Estimate adult size
Works best for dogs. Scroll down for a note on cats.
How this works
Breed and sex set the adult range
We start from the AKC and UKC breed standards, split by sex, then adjust to what healthy pets really weigh: pet toy breeds run bigger than the standard, giant breeds smaller. Mixed pups use a size class instead.
Age and weight project forward
Puppies hit set fractions of adult weight at set ages. Most are about half their adult weight by 4 to 5 months (giant breeds a little later) and about 90% by their first birthday, then keep filling out until about 2. We divide today’s weight by the fraction expected for their size and age.
We weigh both, then give a range
Young puppies lean on the breed range. Older pups lean on their own growth. A pup running well ahead of or behind the breed gets flagged, not stretched into a size the breed doesn’t reach.
Growth curves are fitted to records of about 440,000 US puppies weighed from puppyhood to a healthy adult weight at age 2 to 3 (data from Salt et al. 2017, PLoS ONE, CC BY 4.0) and checked against published growth studies and adult weights from 115,000 dogs (Andersson et al. 2023, Sci Rep). Tested on 94,000 puppies the curves never saw, about half landed inside the “most likely” range and 4 in 5 inside the “could land” range.
Is your puppy on track right now?
Our Puppy Growth Chart plots today’s weight against real puppies of the same breed and sex, and tells you if they’re on track, running small, or running big.
🐱 What about cats?
Most cats land between 8 and 12 pounds as adults, regardless of breed, and are usually full-grown by 12 months. The variability is small, so a calculator doesn’t add much.
The big exceptions are a few larger breeds: Maine Coons (12–20 lb, grow until 4 years), Ragdolls (10–20 lb), Norwegian Forest Cats (12–18 lb), and Savannahs (15–25 lb).