Great Danes reach their full height by around 18 months of age, but they continue filling out with muscle and mass until they are 2 to 3 years old. That means your Great Dane puppy will spend a surprisingly long time in an awkward, lanky phase before looking like a fully mature adult. Understanding the stages of this growth helps you feed them correctly, protect their joints, and know what to expect at each age.
Growth Milestones From Puppy to Adult
Great Danes grow faster than almost any other breed. At 3 months old, a typical puppy already weighs 30 to 45 pounds and stands 17 to 22 inches at the shoulder. By 6 months, that same puppy will weigh 70 to 100 pounds and stand 27 to 33 inches tall. The bulk of their vertical growth happens in this explosive window between 4 and 8 months of age.
At 9 months, most Great Danes weigh 85 to 120 pounds and stand 28 to 34 inches. By their first birthday, they’re typically 90 to 135 pounds and 28 to 36 inches at the shoulder. Height gains slow dramatically after 12 months, with most dogs reaching their final height somewhere between 16 and 18 months. The remaining months are about adding chest depth, muscle, and overall body mass, which continues gradually until age 2 or even 3.
How Big Do They Get?
Adult male Great Danes stand 30 to 32 inches at the shoulder and weigh 140 to 175 pounds. Females are slightly smaller, standing 28 to 30 inches and weighing 110 to 140 pounds. Some individuals exceed these ranges, particularly males from lines bred for size, but these AKC standards give a reliable target for most dogs.
Males tend to take longer to finish filling out than females. A female Great Dane may look fully mature by 2 years old, while a male can still be adding muscle and chest breadth into his third year. If your 18-month-old male looks thin or gangly, that’s perfectly normal.
When Growth Plates Close
Growth plates are soft areas of cartilage near the ends of your dog’s long bones. They’re responsible for lengthening bones during puppyhood, and they gradually harden into solid bone as the dog matures. In most dogs, growth plates close at roughly one year of age, at which point they become invisible or appear as a faint line on X-rays.
This timing matters because open growth plates are vulnerable to injury. A hard fall, repetitive jumping, or forced exercise on hard surfaces during those first 12 months can damage a growth plate and cause the bone to develop unevenly. Because the most intense bone growth happens between 4 and 8 months, injuries during that window carry the highest risk of permanent limb deformities. This is why many veterinarians recommend limiting high-impact activities like long runs, agility courses, and stair-heavy exercise until a Great Dane is at least 12 to 14 months old.
Feeding During the Growth Period
Giant breed puppies need a carefully balanced diet, not just a large one. Overfeeding or supplementing with extra calcium is one of the most common mistakes Great Dane owners make, and it can accelerate bone growth faster than the surrounding cartilage and soft tissue can keep up. The result is skeletal problems that are difficult or impossible to correct later.
The recommended calcium level for large-breed puppies is 0.8% to 1.2% on a dry matter basis, with a calcium-to-phosphorus ratio between 1.1:1 and 2:1. Puppy foods specifically formulated for large or giant breeds are designed to hit these targets. Standard puppy foods, especially “all life stages” formulas, often contain too much calcium for a breed this size. Avoid adding calcium supplements, bone meal, or excessive dairy to your Great Dane puppy’s diet unless a veterinarian has specifically recommended it based on bloodwork.
You want your Great Dane puppy to grow slowly and steadily rather than as fast as possible. A lean, slightly ribby puppy is healthier than a chunky one during this phase. Keeping your puppy on the leaner side reduces stress on developing joints and lowers the risk of growth-related bone disease.
Growth-Related Health Problems to Watch For
Two orthopedic conditions are especially common in Great Danes during their rapid growth phase. Knowing the signs helps you catch them early.
Panosteitis causes a shifting lameness, meaning your puppy may limp on one leg for a few days, then switch to another. The long bones of the legs are painful when pressed. Dogs with panosteitis are otherwise healthy: no fever, no lethargy, just pain that moves around. It’s sometimes called “growing pains” and typically resolves on its own, though it can be severe enough to make a puppy reluctant to walk or eat.
Hypertrophic osteodystrophy is more serious. It causes painful swelling near the ends of the long bones, particularly around the wrists. Unlike panosteitis, dogs with this condition are often visibly sick with fever, lethargy, loss of appetite, and sometimes diarrhea. If your Great Dane puppy under a year old develops swollen, hot joints along with a fever, that warrants urgent veterinary attention.
Spaying and Neutering Timing
In many breeds, early spaying or neutering delays growth plate closure and slightly increases the risk of joint problems. Great Danes appear to be an exception. A large UC Davis study analyzing 15 years of veterinary hospital data found that Great Danes showed no increased risk of joint disorders (hip dysplasia, cranial cruciate ligament tears, or elbow dysplasia) when neutered at any age. This was a surprising finding, as most large breeds did show some age-related effect.
That said, the decision is still a personal one best made with your veterinarian based on your individual dog’s health, behavior, and living situation. The key takeaway is that there’s no strong orthopedic reason to delay the procedure specifically for growth plate concerns in this breed, which simplifies the decision compared to other giant breeds.
Signs Your Great Dane Is Done Growing
Height is the first dimension to finish. If your dog’s shoulder measurement hasn’t changed in two or three months, they’ve likely reached their adult height. Weight and body composition take longer. A Great Dane that looks narrow through the chest at 18 months will often look noticeably broader by age 2.5 to 3 without gaining much additional height.
You can also get a rough sense of remaining growth from paw size. Oversized, clumsy-looking paws on a young Great Dane suggest there’s still significant growth ahead. Once the body “catches up” to the paws, most of the major growth is behind them. The final transformation from adolescent to adult is subtle: a gradual broadening of the head, deeper chest, and thicker musculature that fills out the tall, lean frame they built during their first year and a half.