How this estimate works
The calculator projects adult weight from your puppy's current weight and age using an approximate large-breed growth curve, which estimates the share of adult weight reached at each age. It's a rule of thumb shaped like published growth-standard charts (Salt et al., 2017), not a validated Labrador-specific standard. Puppies grow at different rates, and the best predictor of adult size is still the parents' weights.
| Age | Approx. % of adult weight |
|---|---|
| 8 weeks | 15% |
| 12 weeks | 24% |
| 16 weeks | 34% |
| 20 weeks | 44% |
| 24 weeks | 53% |
| 32 weeks | 68% |
| 40 weeks | 80% |
| 12 months | 92% |
| 18 months | 98% |
| 24 months | 100% |
What to do with the result
- If the projection lands far outside the breed standard (55–80 lb), look at body condition, not just the number. A chubby puppy will project too high.
- Keep puppies lean. Rapid growth and excess weight are linked to hip and elbow problems.
- Recalculate monthly and track the trend.
Gear size-ups as they grow
As the projected adult weight settles in, use the new Lab puppy checklist for when to move the crate divider, upgrade the collar and harness, and switch to adult-size toys (months 3–6).