When Do Dogs Stop Growing? Age by Breed Size, Growth Plates and Cost

Most dogs stop growing between 6 and 24 months of age, and size decides where in that range yours falls. Toy breeds are done at about 6 to 8 months, and giant breeds keep growing until about 2. This guide gives a puppy size chart by breed class, explains growth plates, and shows what the growth years cost for ten breeds.

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Latest news: puppy growth and health in 2026

• No new growth charts. The most cited size-based charts remain the 2017 PLoS One paper below, and its authors called for more validation. We found no peer-reviewed replacement as of October 2026, and web pages that claim 2026 growth breakthroughs gave no traceable source.
• Leptospirosis is now a core vaccine. dvm360's August 2026 interview notes that AAHA made lepto core for all dogs in 2024. A veterinary expert said "lepto is everywhere" and that many people still do not treat it as core.
• A new weight survey is under way. APOP named October 2026 a prevalence study year. Its latest published figure is that 59% of dogs were overweight or obese in 2022.

What it means for you: growth ages have not changed, but the vaccine list has. Ask your vet about leptospirosis when you book the puppy series.

When do dogs stop growing? A puppy size chart by breed class

Dogs stop growing at an age set by adult size. The Elanco puppy growth chart groups breeds into five classes and gives an age for each.

Size class	Adult weight	Examples	When growth stops
Toy	Under 12 lb	Chihuahua, Pomeranian	Around 6-8 months
Small	12-25 lb	Dachshund, Jack Russell Terrier	Under a year, full height near 9 months
Medium	25-50 lb	Border Collie, Dalmatian	About 1 year
Large	50-100 lb	Golden Retriever, German Shepherd	14-18 months
Giant	Well over 100 lb	Great Dane, Newfoundland	About 2 years

Purina's guide to when dogs stop growing gives a wider window of 6 to 24 months. It adds that toy breeds finish at about half the age of larger breeds. Treat both as ranges, not deadlines.

Use this table as your first-pass canine growth chart. It tells you when to stop expecting height gains. It does not predict a final number. For that, see our puppy weight calculator guide.

Why growth stops: how growth plates work

Growth stops when the growth plates close. Purina explains that long leg bones grow from soft, flexible growth plates. New tissue forms there and then hardens into bone. Once a plate stops producing tissue, it is closed, and that bone has reached its final length.

Two practical rules follow from this:

1. Plates close at different times in different bones. A dog can reach full height before every plate is closed.
2. Soft plates are easier to injure. Purina advises avoiding jumping, road running and jogging with dogs under 14 to 18 months, especially large and giant breeds.

A vet can confirm closure with an X-ray. Most owners never need one. Walks, play and gentle training are fine, as long as the puppy sets the pace. Skip the long runs until your vet says the plates are ready.

Does a dog stop growing when it stops getting taller?

No. Height and weight finish at different times. Purina notes that large breeds may fill out further after their bones reach full length. A Labrador that has reached its adult height at 14 months can still gain muscle and chest depth for months.

That is why an adult weight chart is more useful than a single date. Weigh your dog every month through age two. When the number stops climbing for two or three months, growth has ended. Steady gain after that is usually fat, not frame.

How big will a puppy get? What the growth data shows

A large veterinary study shows how much puppies of the same breed class vary. The 2017 PLoS One paper Growth standard charts for monitoring bodyweight in dogs of different sizes drew on records for more than 6 million young dogs. The final models used about 158,000 weight records from roughly 49,700 dogs.

The authors built charts for five size categories, up to a predicted adult weight of 40 kilograms (about 88 pounds). They could not model giant breeds. The charts run from 12 weeks to 2 years. The paper also reports that neutering had only small effects on growth compared with individual variation.

For you, that means three things:

• Size categories help, but they are wide. Two puppies in the same class can differ by many pounds.
• Giant breeds are the least predictable. The data was too thin to chart them.
• Trends beat single weights. A puppy that drifts across centile lines needs a vet's attention.

Determining puppy size works best with three tools: a size class, a growth chart and regular weigh-ins. If you want to know how big a puppy will get, start with the parents' weights. For a mixed-breed puppy, ask your vet for a size range based on its current weight and likely breed mix.

Weight gain during growth: how fast giant puppies grow

Giant puppies gain weight quickly. Elanco says giant breeds typically add 2 to 3 pounds a week, and the largest can gain up to 5 pounds a week. A toy puppy gains a fraction of that.

Fast growth is not better. Overfeeding a large-breed puppy to speed it up can strain young joints. Our Great Dane weight and size guide shows what a giant puppy's weight looks like week by week. Our Great Dane feeding chart shows how food changes with age.

Energy needs change as growth ends. The Merck Veterinary Manual energy table lists these multipliers of resting energy:

Dog's life stage	Multiplier of resting energy
Puppy under 4 months	3.0
Puppy over 4 months	2.0
Neutered adult	1.6
Intact adult	1.8
Obesity-prone adult	1.4

A growing puppy over four months old needs about 25% more calories than a neutered adult of the same weight. Cut the ration as growth ends, or the extra food turns into fat.

Growth checkpoints: what to expect month by month

Growth follows a predictable path, so each month has a job. This table pulls the milestones from AKC, Elanco, Purina and Merck into one timeline.

Age	What is happening	What to do
8 weeks	Most puppies arrive home around now, per AKC	Start weekly weigh-ins and house training
Under 4 months	Highest calorie need, 3.0 times resting energy	Feed several small meals
4 to 5 months	Calorie multiplier drops to 2.0; night potty trips usually end	Recalculate the ration
6 to 8 months	Toy breeds reach full size	Cut calories toward the adult level
9 to 12 months	Small breeds finish; medium breeds reach full size at about 1 year	Check body condition monthly
14 to 18 months	Large breeds finish; plates still closing	Keep exercise gentle, avoid jogging
About 24 months	Giant breeds finish	Switch fully to an adult plan

The calories column is the money column. A 30-pound dog weighs about 13.6 kilograms. Its resting energy is about 70 times 13.6 to the 0.75 power, or roughly 495 calories. A growing puppy at that weight, over four months old, needs about 990 calories. A neutered adult of the same weight needs about 790. That is a 200-calorie gap, and it is the gap that turns into extra weight if the ration never changes.

Mixed-breed puppies: the hardest size to predict

A mixed-breed puppy has the widest range of possible adult sizes. PetBudget's mixed-breed dog profile lists an adult weight of 10 to 90 pounds, a nine-fold spread. A puppy at 12 weeks can sit anywhere in that range.

The PLoS One growth paper helps here. Its five size categories cover predicted adult weights up to 40 kilograms, so most mixed-breed puppies fit one of them. Follow the puppy's weight over time instead of guessing at the start. If the curve flattens at month 10 or 12, you have a medium or small adult. If it keeps climbing past month 14, plan for a large dog.

Cost follows size. PetBudget's mixed-breed dog costs $4,518 in the first year and $2,263 a year after that, with a typical 13-year life. A puppy that turns out larger will cost more for food, medication and insurance than the model's midpoint. Our dog cost guide shows how size changes each line.

How long dogs spend growing, and what it costs

Large dogs spend a much bigger share of their lives growing than small dogs. Using the midpoint of Elanco's age range for each class, and PetBudget's typical lifespan for each breed, the share runs from about 4% to about 25%.

Breed	Size class	Adult weight	Months to full size	Typical lifespan	Share of life growing
Chihuahua	Toy	2-6 lb	7	15 years	4%
Yorkshire Terrier	Toy	4-7 lb	7	13 years	4%
Pug	Small	14-18 lb	10.5	13 years	7%
Pembroke Welsh Corgi	Medium	24-30 lb	12	13 years	8%
Border Collie	Medium	30-45 lb	12	13 years	8%
Labrador Retriever	Large	55-80 lb	16	11 years	12%
German Shepherd	Large	50-90 lb	16	11 years	12%
Bernese Mountain Dog	Giant	70-115 lb	24	8 years	25%
Great Dane	Giant	110-175 lb	24	8 years	25%
Mastiff	Giant	120-230 lb	24	8 years	25%

The size class and lifespan columns come from PetBudget's breed data. Months to full size are class midpoints from Elanco, so the share is an estimate, not a measured value. PetBudget classes the Bernese as giant, although it is lighter than the Elanco examples.

A giant breed spends about one quarter of its life in the most expensive stage. Food shows it clearly. In PetBudget's model, a Great Dane eats about $1,139 of food a year, a Labrador about $732 and a Chihuahua about $78.

The first year is the growth year for most breeds. After that, the yearly cost stays high for big dogs because food, medication and insurance scale with size.

Breed	First-year total	Yearly cost after year one	Lifetime estimate
Chihuahua	$3,905	$1,599	$26,291
Pug	$4,277	$2,202	$30,701
Border Collie	$4,639	$2,384	$33,247
Labrador Retriever	$5,358	$2,813	$33,488
Great Dane	$6,522	$3,674	$32,240

A Great Dane's lifetime estimate is close to a Labrador's even though it costs more per year. The reason is lifespan: PetBudget's typical figure is 8 years for a Great Dane and 11 for a Lab. Run your own breed in the PetBudget calculator.

How to tell when your own dog has stopped growing

Your dog has stopped growing when height and weight stop rising for several weeks. Use this routine.

1. Weigh monthly. Use the same scale at the same time of day. For small dogs, weigh in ounces.
2. Record the number. A note on your phone is enough. Compare the line with your breed's class in the table above.
3. Measure height at the withers if you want to. Stand the dog square against a wall and mark the shoulder.
4. Watch for a plateau. Two or three flat months after the class age means growth is over.
5. Switch the ration to match. Talk to your vet about when to change from puppy food. Do not guess.

The 59% figure matters here. The Association for Pet Obesity Prevention's 2022 survey found that 59% of U.S. dogs were overweight or obese. Dogs are often fed puppy portions for months after growth ends. Check your dog's body condition once the plateau begins.

A puppy that slows early or stalls may have a problem. Elanco names intestinal worms as one cause of slowed growth. If your puppy is under or over the weight for its age, Elanco advises talking to your vet to rule out medical problems.

What to do while your dog is still growing

The growth stage is when habits form. These steps protect the joints and the budget.

• Feed by calories, not by the bag. Use the multipliers above and your food's label. Our puppy feeding calculator guide shows the steps.
• Keep exercise gentle for large breeds. Avoid jumping and road running until your vet clears it, per Purina.
• Book regular weigh-ins. Ask your clinic how often to weigh and chart your puppy.
• Plan the costs. Growth-year costs include vaccines, spay or neuter, a bigger crate and larger collars. See puppy prices by breed and our puppy supplies list.
• Pick a crate for adult size. A crate that fits the adult dog, with a divider, saves buying twice.

Quick answers: when do dogs stop growing?

• Toy breeds: around 6 to 8 months.
• Small breeds: under a year, with full height near 9 months.
• Medium breeds: about 1 year.
• Large breeds: 14 to 18 months.
• Giant breeds: about 2 years.
• After that: weight can still shift, so keep weighing.

For a deeper look at weight formulas and growth charts, read our puppy weight calculator guide. For breed-by-breed costs, browse the breed directory.