Do male puppies grow bigger than females?

Generally yes. Male dogs tend to be 10-20% heavier than females of the same breed at maturity. This difference is more pronounced in larger breeds. Our calculator provides an estimate based on average growth curves — adjust expectations slightly up for males and down for females.

📈 Growth curve data

Puppy Growth Predictor

How big will your puppy get? Enter their current age, weight, and breed size for a science-backed adult weight prediction. Based on Waltham Centre growth curve research and veterinary growth data.

Puppy's current age (months)

Current weight ?

Expected breed size ?

Sex

How to Use This Tool

Enter your puppy's age in months

Use their actual age, not a rounded number. Half months matter for accuracy, especially under 6 months.
Weigh your puppy accurately

For small puppies, weigh yourself holding the puppy, then subtract your weight. For larger puppies, use a pet scale or ask your vet.
Select the breed size category

For mixed breeds, estimate based on parents' size or paw size relative to body. Oversized paws suggest more growth to come.
Review the prediction

The result shows predicted adult weight, current growth progress, and how much more your puppy will likely gain.

Growth Curve by Breed Size

Different sized dogs grow at dramatically different rates. Small breeds reach adult size in under a year, while giant breeds may grow for over two years. This table shows the approximate percentage of adult weight reached at each age:

Age (months)	Toy	Small	Medium	Large	Giant
2	30%	25%	22%	18%	12%
4	55%	48%	40%	33%	24%
6	78%	68%	58%	48%	37%
8	90%	82%	72%	62%	50%
10	97%	92%	83%	73%	60%
12	100%	98%	92%	82%	70%
14	100%	100%	97%	90%	78%
18	100%	100%	100%	97%	90%
24	100%	100%	100%	100%	100%

These values are averages. Individual dogs may vary by 10–15% depending on genetics, nutrition, and whether they've been neutered (early neutering can slightly delay growth plate closure, leading to taller but not necessarily heavier adults).

How We Calculate the Prediction

Our predictor uses a percentage-of-adult-weight model derived from Waltham Centre for Pet Nutrition growth curve data:

Adult Weight Estimation

adult_weight = current_weight ÷ growth_percentage_at_age

Growth percentages are interpolated from breed-size-specific curves published by the Waltham Centre for Pet Nutrition and validated against veterinary clinical data.

For example, if a medium-breed puppy weighs 8 kg at 4 months, and medium puppies are approximately 40% of adult weight at that age:

8 kg ÷ 0.40 = 20 kg estimated adult weight

Sex Adjustment

Male dogs tend to be 5–10% heavier than females of the same breed. We apply a modest adjustment: +5% for males, −5% for females, relative to the breed-average curve.

Frequently Asked Questions

Growth curve predictions are most accurate when the puppy's breed size category is known. For purebred dogs, accuracy is typically within 10–15% of actual adult weight. Mixed breeds are harder to predict, especially if parentage is unknown. The prediction improves as the puppy gets older and closer to its adult weight.

It depends on size. Toy and small breeds (under 10 kg adult) reach full size by 10–12 months. Medium breeds (10–25 kg) finish growing around 12–14 months. Large breeds (25–45 kg) take 14–18 months. Giant breeds (over 45 kg) may not reach full size until 18–24 months.

Look at paw size relative to body (large paws suggest more growth to come), the size of the parents if known, and current weight relative to age. Our calculator uses growth curves — enter the size category that best matches one or both parents. DNA tests can also reveal breed mix and expected size range.

Generally yes. Male dogs tend to be 10–20% heavier than females of the same breed at maturity. This difference is more pronounced in larger breeds. Our calculator applies a modest 5% adjustment for sex. For large and giant breeds, the actual difference may be greater.

Rapid growth can be a concern for large and giant breeds. Growing too fast increases the risk of developmental orthopaedic diseases like hip dysplasia and osteochondritis. Feed a large-breed puppy formula and avoid overfeeding. If your puppy's weight is significantly above the growth curve, consult your vet about adjusting their diet.

Sources

1

Growth Curves for Puppies of Different Breed Sizes

Waltham Centre for Pet Nutrition — The WALTHAM International Science Programme
2

Body-Weight Changes during Growth in Puppies of Different Breeds

Hawthorne et al. (2004) — Journal of Nutrition, Vol. 134
3

Nutrient Requirements of Dogs and Cats

National Research Council (NRC), 2006 — The National Academies Press