Free Tool
Puppy Weight Estimator
How big will my puppy get? Estimate adult weight and size now.
Wondering how big your puppy will get? Our free puppy weight estimator uses your puppy's current age and weight to project their adult size — for small, medium and large breeds.
Please enter a valid weight and age.
- Growth progress
- Expected maturity
Why Puppy Weight Can Be Predicted
A puppy's adult weight is largely determined by breed and parents, not by how much you feed. Most puppies reach a predictable share of their adult weight by a certain age — small breeds are about a third of their adult weight at 8 weeks, and medium/large breeds are about half their adult weight at 16 weeks. From there you can project the final size.
Growth Checkpoints by Size
The standard rule of thumb, based on the AKC breed database: small breeds triple their weight from 8 weeks to adulthood, and medium/large breeds double their weight from 16 weeks to adulthood. If you don't know your puppy's expected adult size (common for mixed breeds), use the medium/large rule — it's the safer general-purpose estimate.
| Size | Adult weight range | Rule of thumb | Typical maturity |
|---|---|---|---|
| Small (< 20 lb adult) | < 20 lb | 8-week weight × 3 | 9–12 months |
| Medium (20–50 lb adult) | 20–50 lb | 16-week weight × 2 | 9–12 months |
| Large (> 50 lb adult) | > 50 lb | 16-week weight × 2 | 12–18 months (giant breeds up to 24) |
Two Ways to Estimate
Age-and-weight method (used above): project forward from your puppy's current age and weight using typical growth curves for their size. Parent-weight method: if you know both parents' adult weights, average them — this is often more accurate than the age-based method alone, especially for mixed breeds.
Frequently Asked Questions
How big will my puppy get?
The standard rule of thumb (based on AKC breed data): small breeds roughly triple their weight between 8 weeks and adulthood, while medium and large breeds roughly double their 16-week weight by adulthood — from there you can project their final size.
How accurate is a puppy weight calculator?
It gives a useful estimate range, not an exact figure. Accuracy improves when you know the parents' weights. Your veterinarian can give a more precise read as your puppy grows.
How much will my puppy weigh when full grown?
Use their current age and weight to project forward — large breed puppies keep growing much longer than small breeds, so the same current weight can lead to very different adult sizes.
When do puppies stop growing?
Toy, small and medium breeds typically finish growing by 9–12 months, large breeds by 12–18 months, and some giant breeds can take up to 24 months.
Estimates use a growth curve anchored to the standard AKC-database-based rule of thumb (small: 8-week weight × 3; medium/large: 16-week weight × 2) and are not a substitute for veterinary guidance — actual adult size varies by individual dog.