🧮 Puppy Adult Weight Calculator: Predict Your Puppy's Adult Size
Enter your puppy's age and current weight to estimate their adult size.
Predict your puppy's adult weight using their current age and weight with this proven formula.
Enter your puppy's age and current weight to estimate their adult size.
Knowing approximately how big your puppy will get helps you make important decisions right now: choosing the right crate size, selecting appropriate food, budgeting for future costs, and planning your living situation.
The most reliable prediction method between 14-20 weeks is the age-weight ratio formula: take current weight, divide by age in weeks, multiply by 52, then apply a size-specific correction factor. This calculator uses that approach. It works best for pure breeds or dogs whose adult size category is known. For mixed breeds, a DNA breed test significantly improves prediction accuracy.
Results carry a margin of error of approximately 10-15%. Even littermates from the same parents can vary significantly in adult size — genetics is complex and not fully predictable from early weight alone. Use the result as a planning guide, not a guarantee. Asking your breeder for parent weights and previous litter adult weights gives the most reliable additional data point.
Once you have your adult size estimate, use our Dog Crate Size Calculator to find the right dimensions for your adult dog. Buying an adult-sized crate with a divider panel now rather than a puppy crate saves money and prevents the disruption of changing crates mid-training.
The most accurate predictors in order: (1) DNA breed test showing exact breed composition, (2) parent weights for pure breeds, (3) previous litter adult weights, (4) the age-weight formula used in this calculator between 14-20 weeks. No method is perfectly accurate — genetics has inherent variation even with all this information.
Generally yes — males of most breeds average 10-20% larger than females in adult weight. This calculator does not adjust for sex because the difference varies significantly by breed. If you know your puppy's sex, the adult weight estimate may skew slightly low for males and slightly high for females.
Between 14-20 weeks of age for medium breeds. Younger puppies have more variable growth rates. For toy breeds, accuracy improves between 10-16 weeks. For giant breeds, 16-24 weeks gives the best results. Calculate at multiple ages and average the results for better accuracy.
Buy adult-sized with a divider. A wire crate with a divider panel lets you create the correct smaller puppy space now and expand as they grow — saving you from buying multiple crates. Use this calculator's adult weight estimate with the Crate Size Calculator to find the right adult dimensions.