When Does My Puppy Finish Growing?
Post Date:
October 24, 2023
(Date Last Modified: November 13, 2025)
Puppy growth is a stepwise process in which body size, bones, and behavior change as the animal matures. Observing physical milestones and adjusting care for breed and size helps owners support healthy development.
Growth Phases and Timeline
Newborn puppies progress through recognizable phases including neonatal, socialization, juvenile, adolescent, and adult stages, each defined by typical age ranges and behavioral features; the neonatal period generally ends by about 2 weeks of age [1].
The socialization window commonly spans roughly 3 to 12 weeks and is the prime time for safe exposure to people and other animals [1].
The juvenile phase commonly covers approximately 3 to 6 months when rapid physical growth occurs and primary puppy teeth fall out [1].
Adolescence often begins around 6 months and can extend to 12–24 months depending on breed, during which hormonal changes and behavioral testing of limits appear [1].
Full adult physical maturity in small breeds may arrive earlier while larger breeds finish later; size and breed drive much of the timing and variability in these phase transitions [1].
Size Categories and Expected Growth Durations
Breeds are commonly grouped as small, medium, large, and giant for growth expectations, and typical adult-size ages vary across these categories [2].
| Size category | Typical age at adult size | Example breeds | Notes |
|---|---|---|---|
| Small | 6–9 months [2] | Chihuahua, Toy Poodle | Faster skeletal closure, longer lifespan on average |
| Medium | 9–12 months [2] | Cocker Spaniel, Bulldog | Intermediate pace of growth |
| Large | 12–18 months [2] | Labrador Retriever, German Shepherd | Prolonged growth of long bones |
| Giant | 18–24+ months [2] | Great Dane, Mastiff | Skeletal maturity often completes after 18 months |
Size predicts growth rate because larger breeds experience prolonged endochondral bone growth and delayed growth plate closure compared with small breeds, which affects final height and the timing of orthopedic risks [2].
Skeletal and Physical Milestones
Owners can track measurable changes to gauge progress: regular weight checks, height measurements at the shoulder, tooth eruption schedules, and coat transitions are practical markers [3].
- Weigh puppies weekly for the first 16 weeks, then monthly until growth slows; plotting weight on a growth chart reveals deviations from expected curves [3].
- Deciduous teeth usually erupt by 3–8 weeks and begin to be replaced between about 3 and 7 months, with most adult teeth present by 6–8 months [3].
- Coat changes—from softer puppy coat to adult coat—often start between 4 and 12 months depending on breed and can be used along with weight and height to track maturity [3].
Muscular development and shifts in body proportions (leg length relative to torso) become noticeable during the juvenile and adolescent phases as bones grow and muscle mass accrues with activity and nutrition [3].
Growth Plate Closure and Bone Maturation
Growth plates (physes) in long bones close at different ages based on size and location; for many small breeds closure occurs by roughly 6–12 months while giant breeds may not complete closure until 18–24 months or later [4].
Veterinarians assess physeal closure with radiographs by looking for disappearance of the growth plate line and appearance of mature trabecular bone; specific timing for individual bones can vary considerably [4].
Because open growth plates are vulnerable to injury and because some elective orthopedic procedures are best delayed until plates are closed, timing surgery often depends on confirmed radiographic maturity rather than age alone [4].
Nutrition and Diet for Growing Puppies
Puppy diets are formulated with higher protein and calorie density and different calcium:phosphorus ratios than adult diets to support tissue growth and skeletal development [5].
General feeding frequency recommendations include multiple small meals daily: for example many breeders and clinicians recommend feeding puppies 3–4 times per day until about 6 months, then transitioning to 2 meals per day for adults, but specific schedules should follow life stage and body condition [5].
Calorie management is important: excess calories in large-breed puppies can accelerate growth and increase risk of hip and elbow dysplasia, while calorie restriction can stunt growth if below needs; targeted feeding plans use expected adult weight to set daily calories and adjust as the puppy grows [5].
Calcium and phosphorus must be balanced; supplemental calcium given free-choice or in excess can cause skeletal abnormalities in large-breed puppies, so additional mineral supplements should only be used under veterinary guidance [5].
Exercise, Activity Limits, and Joint Health
Age- and size-appropriate activity promotes muscle and bone strength while avoiding repetitive high-impact loading during the phase of rapid bone growth [1].
For many puppies, short walks several times daily that total 5–30 minutes depending on age and size are suitable; very young or giant-breed puppies should have shorter, low-impact play sessions rather than long runs or jumping sequences [1].
Avoid repetitive stair climbing, high-impact repetitive jumping, and long-distance running until skeletal maturity is confirmed; these activities increase shear and torsional forces across open physes and can raise orthopedic injury risk [1].
Hormonal Influences and the Impact of Spay/Neuter
Sex hormones influence the timing of growth plate closure: delaying spay or neuter can prolong the period of open growth plates and may result in slightly taller adult stature in some breeds, while early sterilization can accelerate closure in other contexts; clinical studies vary by outcome and breed [2].
Evidence on orthopedic outcomes with early versus delayed sterilization shows mixed effects by breed and outcome measure, so decisions should balance orthopedic risk, behavior, and population-health benefits with individualized veterinary advice [2].
Common Growth Concerns and Red Flags
Warning signs that warrant veterinary evaluation include asymmetric limb length, a limp or non-weight-bearing lameness, marked deviation from expected growth curves, excessive thinness, or rapid unwarranted weight gain [3].
Potential causes of abnormal growth include congenital orthopedic disease, nutritional imbalance, growth-hormone disorders, hypothyroidism, or trauma; diagnostics commonly used are radiographs, orthopedic exams, and targeted bloodwork [3].
If a puppy shows persistent lameness or asymmetric limb development for more than a few days, or if weight fails to increase according to expected curves, schedule a veterinary visit and consider imaging to rule out physeal fractures or developmental joint disease [3].
Monitoring Growth at Home and with Your Vet
Plot weight on a chart using the puppy’s recorded weights to detect upward or downward trends; bring the plotted growth chart, measured height at the shoulder, and a sequence of photos (monthly) to veterinary appointments for trend review [4].
Frequent early checks—such as at 6–8 weeks, 12 weeks, 6 months, and at or near anticipated skeletal maturity by breed—help detect deviations; your veterinarian may request radiographs if growth is asymmetric or if surgical planning depends on physeal status [4].
When requesting radiographs for growth-plate assessment, vets typically obtain orthogonal views of affected limbs and compare physeal lines to expected closure patterns for the puppy’s size and breed [4].
Behavioral and Cognitive Maturity vs Physical Maturity
Behavioral maturity often lags behind physical maturity; many dogs reach emotional regulation and full impulse control between 1 and 4 years of age depending on breed and individual temperament [5].
Adolescent behaviors—such as increased testing of boundaries, reactivity, or selective listening—can continue well after the body has reached adult size, so training and socialization should be maintained into the second year and beyond as needed [5].
Adjust expectations by separating milestones: use physical measures (weight, height, growth plate status) to plan activity and surgical timing, and use behavioral assessments to guide training intensity and social supports [5].
Sources
- merckvetmanual.com — veterinary clinical reference
- aaha.org — American Animal Hospital Association guidance and position statements
- avma.org — American Veterinary Medical Association resources on growth and health
- wsava.org — World Small Animal Veterinary Association position papers and clinical resources
- vcahospitals.com — veterinary specialty hospital guidance on nutrition, behavior, and orthopedics
