Puppy Growth Weight Predictor
Enter your puppy's current weight and age in weeks to get a rough estimate of adult weight, using a commonly cited general guideline. This is a general estimate, not a breed-specific prediction — actual adult size varies significantly by breed.
How the Puppy Growth Weight Predictor formula works
A widely cited general guideline for medium-to-large breeds:
Estimated adult weight ≈ Weight at 16 weeks × 2
For puppies not yet at 16 weeks, current weight is scaled proportionally as a rougher approximation.
Step-by-step calculation
- If your puppy is at or near 16 weeks old, roughly double its current weight for an estimated adult weight.
- For younger puppies, this calculator scales the estimate proportionally, though accuracy decreases the further from 16 weeks the current age is.
Worked example
A 16-week-old puppy weighing 20 lb: Estimated adult weight ≈ 20 × 2 = 40 lb.
Frequently asked questions
How accurate is this estimate?
It's a rough general guideline, not a precise prediction — actual adult size depends heavily on breed, genetics, and individual growth patterns. Toy and small breeds mature faster and don't follow this same doubling pattern as well as medium-to-large breeds. A veterinarian familiar with your puppy's breed can give a more informed estimate.
Why does the 16-week mark matter?
Many medium-to-large breed puppies reach roughly half their adult weight around 16 weeks of age, which is why that age is commonly used as a reference point for this kind of rough doubling estimate.