The puppy weight calculator
Science-backed predictions from veterinary growth research on 8 million+ vet records
Predicted weight progression from birth to adult size
Science-backed predictions using veterinary growth research
Unlike simple calculators that use a basic "double it at 4 months" formula, the puppy weight calculator combines three prediction methods, all grounded in peer-reviewed veterinary data:
We use age-specific growth completion percentages derived from a peer-reviewed study (Salt et al., 2017) of over 8 million vet-measured weight records from Banfield Pet Hospitals. Dogs of similar adult weight follow remarkably similar growth curves, which allows us to predict adult size from a puppy's current weight and age. These curves are sigmoid-shaped (S-curves), meaning growth is slow at first, accelerates, then gradually levels off.
When you select a breed, we incorporate the American Kennel Club's official weight ranges for that breed and sex. This anchors the prediction within a genetically plausible range, preventing wild over- or under-estimates that plague simpler calculators.
For the most accurate prediction, you can provide your puppy's parents' weights. This is especially valuable for mixed breeds or breeds with wide weight ranges, as the parents' size is the strongest single predictor of a puppy's adult weight.
Our algorithm dynamically adjusts how much it relies on each method based on your puppy's age. For very young puppies (under 8 weeks), breed data is weighted more heavily since the growth table is less reliable at early ages. As your puppy ages and we have more growth data to work with, the growth completion tables become the dominant prediction factor.
Growth rates and timelines vary significantly by size
| Category | Adult Weight | Full Grown By | Example Breeds |
|---|---|---|---|
| Toy | Under 14 lbs | 8-10 months | Chihuahua, Yorkshire Terrier, Pomeranian |
| Small | 14-25 lbs | 10-12 months | French Bulldog, Miniature Schnauzer, Cavalier King Charles |
| Medium | 25-50 lbs | 12-15 months | Beagle, Border Collie, Cocker Spaniel |
| Large | 50-90 lbs | 14-18 months | Labrador, Golden Retriever, German Shepherd |
| Giant | Over 90 lbs | 18-24 months | Great Dane, Saint Bernard, Newfoundland |
Buy for their adult size, not their puppy size
Once you know your puppy's predicted adult weight, you can start buying the right gear from the start. Puppies grow fast. A crate or harness that fits today might be too small in a few weeks. Sizing for their adult weight up front saves you from buying the same thing twice.
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A crate should be large enough for your adult dog to stand up, turn around, and lie down without crouching. Too large and your puppy may use one end as a bathroom during house training. The fix: buy the adult size and use the divider panel that comes with most wire crates. Slide the divider back as your puppy grows, and you only ever buy one crate.
| Size Category | Crate Length | Fits Dogs Up To |
|---|---|---|
| Toy | 22-inch crate | ~12 lbs |
| Small | 24-inch crate | ~25 lbs |
| Medium | 36-inch crate | ~50 lbs |
| Large | 42-inch crate | ~90 lbs |
| Giant | 48-inch crate | 90+ lbs |
Not all puppy food is the same. The formula changes based on your dog's expected adult size. Large and giant breed puppy food has controlled calcium-to-phosphorus ratios that prevent bones from growing too quickly. Rapid bone growth in big puppies raises the risk of hip dysplasia and other orthopedic problems. Small breed puppy food uses smaller kibble for tiny mouths and packs more calories per cup because small dogs burn energy faster relative to their size.
Feed puppy food matched to their size until your dog reaches their adult weight (check the timelines above), then switch to an adult food.
| Size Category | Recommended Food Type | Why It Matters |
|---|---|---|
| Toy / Small | Small breed puppy formula | Smaller kibble, higher calorie density |
| Medium | All-breed puppy formula | Balanced nutrition for moderate growth rates |
| Large | Large breed puppy formula | Controlled calcium and phosphorus |
| Giant | Large/giant breed puppy formula | Controlled minerals, added joint support |
Most trainers and vets will tell you the same thing: skip the collar, get a harness. Collars concentrate force on the neck, which can damage a developing trachea. This is especially true for small breeds and brachycephalic (flat-faced) breeds that are already prone to breathing issues. A harness spreads force across the chest instead, giving you better control on walks without the risk of neck strain.
For a growing puppy, pick your harness by weight range instead of chest measurements. They'll outgrow exact numbers fast. Look for a harness with multiple adjustment points so it lasts through more of the growth phase.
| Size Category | Harness Size | Typical Chest Girth |
|---|---|---|
| Toy | XXS–XS harness | 12–16 inches |
| Small | Small harness | 16–20 inches |
| Medium | Medium harness | 20–26 inches |
| Large | Large harness | 26–32 inches |
| Giant | XL harness | 32–40+ inches |
Growth timelines depend on your dog's adult size
One of the most common questions new puppy owners ask is "when will my puppy stop growing?" The answer depends almost entirely on your dog's size category. Smaller breeds reach their adult weight much faster than larger breeds, which continue growing for up to two years.
These timelines represent skeletal growth — when your puppy's bones stop lengthening and the growth plates close. However, dogs may continue to fill out with muscle and reach their final body composition for several months after skeletal growth ends. A Great Dane, for example, may reach its full height by 18 months but continue adding muscle mass until age 2–3.
There is an important distinction between a dog reaching its adult height and reaching its adult weight. Height (skeletal growth) stops when the growth plates at the ends of the long bones close. Weight can continue to increase as the dog adds muscle and body mass. For most breeds, height is reached first, followed by full body weight several weeks to months later.
You can tell your puppy is nearing adult size when their weight plateaus over consecutive monthly weigh-ins, their paws no longer look oversized relative to their legs, and their body proportions begin to look balanced rather than gangly. Our calculator shows your puppy's current growth percentage, which helps you track exactly where they are in their growth journey.
Read more: When do large breed puppies stop growing? · When do small dogs stop growing?
What to expect from birth to adulthood
Every puppy goes through the same developmental stages, though the timing varies by breed size. Understanding these stages helps you know what to expect and when your puppy's growth rate is normal. For a complete week-by-week breakdown, see our puppy growth stages guide.
Puppies are born blind and deaf, relying entirely on their mother. Weight typically doubles during this stage. Birth weight varies dramatically by breed: a Chihuahua puppy may weigh 2–5 oz, while a Great Dane puppy may weigh 1–2 lbs.
Eyes and ears open. Puppies begin to stand and take their first wobbly steps. Baby teeth start to emerge. Growth is rapid — puppies may gain 5–10% of their body weight daily during this period.
The fastest growth period for most breeds. Puppies are weaned from their mother and transition to solid food. By 8 weeks, small breeds may already be 30–35% of their adult weight, while large breeds are only 15–20%.
Growth rate is highest during this period. Puppies look gangly as their legs grow faster than their bodies. Adult teeth replace baby teeth. Toy and small breeds may reach 50–65% of their adult weight by 4 months (16 weeks), while large breeds reach only 40–45%. This is also when most owners start crate training — choosing a crate sized for your puppy's adult weight with a divider panel means you only buy one.
Growth rate slows progressively. Small breeds approach adult size by the end of this stage. Large and giant breeds are still actively growing but at a decreasing rate. This is when body proportions start to balance out.
Skeletal growth is complete and weight stabilizes. Small breeds reach this stage by 10–12 months, while giant breeds may not be fully mature until 2–3 years. Dogs continue to develop muscle mass and may fill out slightly even after reaching full height.
Genetics, nutrition, and other influences on growth
While breed is the strongest predictor of adult size, several factors can influence how large your puppy ultimately grows and how quickly they get there.
Genetics accounts for the largest share of your puppy's final size. Within a breed, adult weight can still vary by 10–20% between individuals — this is why knowing the parents' weights provides the most accurate prediction for any individual puppy. Mixed breed puppies inherit size genes from both parents, and their adult size typically falls between the two parents' weights, though this is not always exact due to how size genes interact.
Proper nutrition supports healthy growth but does not cause a puppy to grow larger than their genetic potential. However, poor nutrition can stunt growth. Overfeeding is equally harmful — puppies that gain weight too quickly (especially large and giant breeds) are at higher risk for developmental orthopedic diseases including hip dysplasia and osteochondritis. Feed a puppy-specific food formulated for your dog's expected adult size, and follow your veterinarian's feeding guidelines. Large breed and small breed formulas are not interchangeable — see our size-specific food recommendations below.
Early spaying or neutering (before 6 months) can slightly affect final adult size. Sex hormones signal the growth plates to close; without these hormones, growth plates may remain open slightly longer, resulting in a dog that is marginally taller but often with a leaner build. The effect is modest — typically 1–2% of overall height — and varies by breed and timing of the procedure. Discuss optimal timing with your veterinarian.
Regular, age-appropriate exercise supports healthy bone and muscle development. However, excessive high-impact exercise (long runs, repeated jumping) during the growth phase can damage developing growth plates, particularly in large and giant breed puppies. The general guideline is 5 minutes of exercise per month of age, twice per day, until the puppy is fully grown. A well-fitted harness is safer than a collar for walks during the growth phase, as it avoids pressure on the developing trachea.
Intestinal parasites, chronic infections, and certain hormonal conditions can slow or stunt growth. Puppies with heavy parasite loads may fail to gain weight at a normal rate despite adequate feeding. Growth hormone deficiencies, while rare, can result in proportional dwarfism. If your puppy's weight is consistently below expectations for their breed, consult your veterinarian to rule out underlying health issues.
How to assess your puppy's body condition
Knowing your puppy's predicted adult weight is helpful, but it is equally important to make sure they are growing at a healthy rate right now. Veterinarians use a Body Condition Score (BCS) on a 1–9 scale to assess whether a dog is underweight, ideal, or overweight.
| Score | Condition | What You See and Feel |
|---|---|---|
| 1–3 | Underweight | Ribs, spine, and hip bones easily visible. Little or no body fat. Obvious waist and abdominal tuck. |
| 4–5 | Ideal | Ribs easily felt with slight fat covering but not visible. Visible waist when viewed from above. Abdominal tuck present when viewed from the side. |
| 6–7 | Overweight | Ribs difficult to feel under fat. Waist barely visible or absent. Abdomen may appear rounded. |
| 8–9 | Obese | Ribs not palpable under thick fat. No waist visible. Obvious abdominal distension. Fat deposits on neck and limbs. |
Run your hands along your puppy's ribcage. You should be able to feel each rib without pressing hard, with a thin layer of fat over them. Looking at your puppy from above, you should see a visible waist (an inward curve behind the ribs). From the side, the abdomen should tuck upward from the ribcage toward the hind legs.
Consult your veterinarian if your puppy's weight is more than 20% above or below the expected range for their breed and age, if they are gaining weight too rapidly (especially large and giant breeds), if they have lost weight unexpectedly, or if you are unsure how much to feed them. Your vet can establish a healthy growth plan tailored to your specific puppy.