Predicted Adult Weight
27 lbs
Range
23–31 lbs
Grown
58%
Full Size In
~10 mo
Predicted Adult Weight
27
lbs (23\u201331 lbs range)
Steady Growth
Past the halfway mark. Growth rate is stabilizing.
% Grown
58%
Full Size In
~10 mo
Past halfway! Growth rate is slowing down.
50% adult weight
~16 weeks
75% adult weight
~24 weeks
Full size
14 months
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Inputs
Result
A medium breed puppy at 14 weeks is about 50% of adult weight. 15 / 0.50 = 30 lbs base. Male adjustment (+5%): 30 × 1.05 = 31.5, rounded to 32 lbs. Range: 27–36 lbs (±15%).
Inputs
Result
A large breed puppy at 20 weeks is about 50% of adult weight. 25 / 0.50 = 50 lbs base. Female adjustment (-5%): 50 × 0.95 = 47.5, rounded to 48 lbs. Range: 40–55 lbs (±15%).
Inputs
Result
A toy breed puppy at 12 weeks is about 75% of adult weight. 3 / 0.75 = 4.0 lbs. Male adjustment (+5%): 4.0 × 1.05 = 4.2, rounded to 4 lbs. Range: 4–5 lbs (±15%).
Breed-based weight formulas are typically 75–85% accurate for purebred dogs when measured at 14–16 weeks. Mixed breeds have wider variance, dropping to 60–75% accuracy. The best predictions combine age, current weight, and breed-size growth curves.
| Breed Size | Adult Weight Range | Growth Complete By |
|---|---|---|
| Toy | 2–12 lbs | 9–12 months |
| Small | 12–25 lbs | 9–12 months |
| Medium | 25–50 lbs | 12–15 months |
| Large | 50–100 lbs | 15–18 months |
| Giant | 100–200 lbs | 18–24 months |
Toy and small breeds reach adult weight by 9–12 months. Medium breeds finish by 12–15 months. Large breeds take 15–18 months, and giant breeds like Great Danes may continue growing until 18–24 months.
| Breed Size | 50% Weight | 75% Weight | Full Size |
|---|---|---|---|
| Toy/Small | 12 weeks | 16 weeks | 9–12 months |
| Medium | 16 weeks | 24 weeks | 12–15 months |
| Large | 20 weeks | 30 weeks | 15–18 months |
| Giant | 24 weeks | 40 weeks | 18–24 months |
Yes, male dogs typically weigh 5–20% more than females of the same breed. In toy breeds the difference may be only 1–2 lbs, while in giant breeds males can outweigh females by 20–40 lbs. This calculator applies a ±5% gender adjustment.
| Breed Size | Male Premium | Example |
|---|---|---|
| Toy | 5–10% | Chihuahua: 4–6 lbs vs 3–5 lbs |
| Medium | 10–15% | Bulldog: 50 lbs vs 40 lbs |
| Large | 15–20% | Lab: 70 lbs vs 60 lbs |
| Giant | 15–25% | Great Dane: 150 lbs vs 120 lbs |
For mixed breeds, use the generic formula: (current weight / age in weeks) × 52. If parents are known, average their weights. DNA breed testing ($100–$200) can improve accuracy to 85–90% by identifying the size groups in the mix.
| Method | Accuracy | Cost |
|---|---|---|
| Parent average | 80–85% | Free |
| Generic formula | 65–75% | Free |
| DNA breed test | 85–90% | $100–$200 |
Switch timing depends on breed size. Toy/small breeds can transition at 9–12 months, medium breeds at 12–14 months, and large/giant breeds should stay on puppy food until 14–24 months to support bone and joint development.
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Last Updated: Mar 26, 2026
This calculator is provided for informational and educational purposes only. Results are estimates and should not be considered professional financial, medical, legal, or other advice. Always consult a qualified professional before making important decisions. UseCalcPro is not responsible for any actions taken based on calculator results.