How can I predict how big my puppy will get?

Our puppy growth predictor uses breed size growth curves. Enter your puppy's current age (in weeks), weight, and expected adult size. The tool interpolates from standardized growth curves to estimate adult weight with ±15% variance.

Does paw size predict a puppy's adult size?

Partially. Large paws relative to body size can indicate significant growth ahead, but it's not a reliable metric on its own. Breed genetics and growth curves are much more accurate predictors. Other indicators include loose skin (room to grow into) and the puppy's current position on standardized breed growth charts. Our calculator combines your puppy's current weight and age with breed-specific growth curves, which is the most scientifically validated prediction method. For mixed breeds, we use the expected adult size category (small/medium/large/giant) you select.

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Puppy Adult Weight Predictor

Predict how big your puppy will get using breed size and growth curves. Track weight milestones with an interactive growth chart.

子犬の現在の年齢（週）

現在の体重

予想成犬サイズ

小型< 10 kg · トイ＆小型犬種中型10–25 kg · 中型犬種大型25–45 kg · 大型犬種超大型> 45 kg · 超大型犬種

主要な知識

How Big Will My Puppy Get?

Puppy growth follows breed-size curves: small breeds fully grown by 8-10 months, giant breeds continue until 18-24 months. Puppy growth follows a breed-size-specific curve. Small breed puppies (<10 kg adult weight) reach 75% of adult weight by 5 months and are fully grown by 8-10 months. Giant breeds (>45 kg) don't reach 75% of adult weight until 8-10 months and continue growing until 18-24 months.

Source: UCSD Growth Curve Research

Why Breed Size Determines Growth Rate

Large breed puppies have rapid skeletal growth — overfeeding increases risk of hip dysplasia and other developmental orthopedic diseases. Large and giant breed puppies have disproportionately fast skeletal growth to reach their adult frame. This rapid growth comes with risks — if overfed, large breed puppies are at higher risk for developmental orthopedic diseases (hip dysplasia, OCD). Controlled growth, not maximum growth, is the goal. Feed a large-breed puppy formula with appropriate calcium-to-phosphorus ratios.

Source: AAHA Canine Life Stage Guidelines

When Do Puppies Stop Growing?

Small breeds: 8-10 months. Medium: 12-14 months. Large: 14-18 months. Giant: 18-24 months. Growth plate closure confirms skeletal maturity. Small breeds (<10 kg): 8-10 months. Medium breeds (10-25 kg): 12-14 months. Large breeds (25-45 kg): 14-18 months. Giant breeds (>45 kg): 18-24 months. Growth plate closure — the definitive sign of skeletal maturity — follows this timeline. Your vet can confirm closure via X-ray if needed.

Source: AKC Breed Standards

How Accurate Is the Prediction?

Accuracy improves with age: ±20% at 8 weeks, ±12% at 16 weeks, ±8% by 6-10 months. Purebred predictions are more accurate than mixed breeds. Our calculator uses non-linear growth curves calibrated to AKC breed weight standards and UCSD growth data. Accuracy depends on the puppy's age: predictions at 8 weeks have wider confidence intervals (±20%). By 16 weeks, predictions narrow to ±12%. By 6 months (small breeds) or 10 months (large breeds), projections are ±8%. Purebreds are more predictable than mixed breeds.

Source: UCSD Dog Aging Project

petsMetricsが査読付き獣医ソースを使用して検証したデータ。引用：ASPCA、AVMA、AAFP。最終レビュー：2026。

The Science Behind the Puppy Growth Predictor

Our predictor uses sigmoid (S-shaped) growth curves fitted to breed-specific adult weight data from AKC breed standards. The formula is: AdultWeight = CurrentWeight × (1 + (AdultWeight/CurrentWeight - 1) × e^(-k × t)), where k is a breed-size-specific growth rate constant and t is time to maturity. Small breeds (k ≈ 0.45, maturity ~10 months) vs. giant breeds (k ≈ 0.18, maturity ~22 months). The prediction is anchored by your puppy's current position on this curve. UCSD Dog Aging Project growth data and AAHA life stage guidelines validate the curve parameters.

References: UCSD Dog Aging Project — Growth Data; AAHA Canine Life Stage Guidelines (2021)— via petsMetrics

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