How Big Will My Puppy Get?
Adult size is predictable once you know two things: your puppy's size tier, and how far along their growth curve they currently are.
Enter your puppy's breed, current weight, and age to estimate their adult weight.
Calculate My Puppy's Adult Weight →It's not just current weight × a fixed number
A common shortcut is doubling a puppy's weight at a certain age, but that only works loosely and only for a narrow age window. The real driver is what share of adult weight a puppy has typically reached at their current age — and that share depends heavily on what size the puppy will end up being as an adult.
Growth speed by size tier
- Toy (under 10 lbs adult): grows fast and finishes early, usually reaching full size by around 10–11 months.
- Small (10–30 lbs adult): also finishes relatively early, typically by around a year.
- Medium (30–50 lbs adult): moderate pace, usually done growing by around 14 months.
- Large (50–100 lbs adult): slower and steadier, often still filling out until around 18 months.
- Giant (over 100 lbs adult): the slowest to mature, commonly still growing until close to 2 years old.
This is the opposite of what a lot of owners expect — the biggest dogs take the longest to get there, not the shortest.
Why mixed breeds are harder to predict
If you know the breed, its typical size tier does most of the work. For mixed-breed puppies, the best approach is estimating the closest size tier based on current build, paw size, and parentage if known — genetics and littermate size can shift the outcome, so treat any estimate as a ballpark rather than a guarantee.
Estimate your puppy's adult weight
Use the Puppy Weight Calculator to get a specific number based on your puppy's breed (or closest size tier), current weight, and age in weeks. To see the full growth curve laid out by week and size, check the Puppy Growth Chart by Size. And if you're wondering when the growing actually stops, see When Do Puppies Stop Growing?