Use our free dog size calculator by breed to find your dog’s predicted adult size, weight range, and size category. Enter your dog’s breed to get adult weight, height at withers, and how your current puppy size compares to the expected adult.
Dog Size Calculator: How Big Will My Dog Get?
Adult dog size is primarily determined by genetics and breed. The most reliable method for predicting puppy adult size is using breed standards combined with the puppy’s current weight and age. Smaller breeds reach adult size earlier (9–12 months); giant breeds can continue growing until 18–24 months.
Dog Size Categories
| Size Category | Adult Weight | Height at Withers | Age at Full Size |
|---|---|---|---|
| Toy | Under 10 lb (4.5 kg) | 6–10 inches | 9–10 months |
| Small | 10–25 lb (4.5–11 kg) | 10–15 inches | 10–12 months |
| Medium | 25–60 lb (11–27 kg) | 15–22 inches | 12–15 months |
| Large | 60–100 lb (27–45 kg) | 22–27 inches | 15–18 months |
| Giant | Over 100 lb (45 kg+) | 27+ inches | 18–24 months |
Dog Size Calculator by Breed
| Breed | Size | Male Weight | Female Weight | Height (withers) |
|---|---|---|---|---|
| Chihuahua | Toy | 4–6 lb | 4–6 lb | 6–9 in |
| Yorkshire Terrier | Toy | 7 lb max | 7 lb max | 7–8 in |
| Pomeranian | Toy | 3–7 lb | 3–7 lb | 6–7 in |
| Shih Tzu | Small | 9–16 lb | 9–16 lb | 9–10.5 in |
| Beagle | Small | 20–30 lb | 20–30 lb | 13–15 in |
| French Bulldog | Small | 20–28 lb | 16–24 lb | 11–13 in |
| Miniature Schnauzer | Small | 11–20 lb | 11–20 lb | 12–14 in |
| Cocker Spaniel | Medium | 25–30 lb | 20–25 lb | 14.5–15.5 in |
| Border Collie | Medium | 30–55 lb | 27–45 lb | 18–22 in |
| Bulldog | Medium | 50 lb | 40 lb | 14–15 in |
| Australian Shepherd | Medium | 50–65 lb | 40–55 lb | 18–23 in |
| Labrador Retriever | Large | 65–80 lb | 55–70 lb | 22.5–24.5 in |
| Golden Retriever | Large | 65–75 lb | 55–65 lb | 21.5–24 in |
| German Shepherd | Large | 65–90 lb | 50–70 lb | 22–26 in |
| Boxer | Large | 65–80 lb | 50–65 lb | 21.5–25 in |
| Siberian Husky | Medium–Large | 45–60 lb | 35–50 lb | 20–23.5 in |
| Doberman Pinscher | Large | 75–100 lb | 60–90 lb | 24–28 in |
| Rottweiler | Large | 95–135 lb | 80–100 lb | 22–27 in |
| Great Dane | Giant | 140–175 lb | 110–140 lb | 28–32 in |
| Saint Bernard | Giant | 140–180 lb | 120–140 lb | 26–30 in |
| Mastiff | Giant | 160–230 lb | 120–170 lb | 27.5+ in |
| Bernese Mountain Dog | Large–Giant | 80–115 lb | 70–95 lb | 23–27.5 in |
Puppy Size Calculator: Predict Adult Weight
For mixed breeds or when exact breed is unknown, use these formulas based on puppy weight and age:
| Breed Size | Formula | Example |
|---|---|---|
| Small (under 25 lb adult) | Weight at 6 weeks × 4 | 2 lb at 6 weeks → ~8 lb adult |
| Medium (25–50 lb adult) | Weight at 14 weeks × 2.5 | 10 lb at 14 weeks → ~25 lb adult |
| Large (50–100 lb adult) | Weight at 16 weeks × 2 | 25 lb at 16 weeks → ~50 lb adult |
| Giant (100 lb+ adult) | Weight at 20 weeks × 2 | 50 lb at 20 weeks → ~100 lb adult |
These formulas give estimates. Mixed breeds vary widely. For the most accurate prediction, combine formula results with the known breeds in your dog’s DNA.
What Size Dog Should I Get?
| Living Situation | Recommended Size | Why |
|---|---|---|
| Small apartment, city living | Toy to small | Lower exercise demands; fits smaller spaces |
| Apartment with park access | Small to medium | Good balance of adaptability and activity |
| House with yard | Any size | Most sizes thrive with yard access |
| Active lifestyle, outdoor sports | Medium to large | Better stamina for running, hiking, sport |
| Farm or rural property | Large to giant | Space and working-dog roles |
| Family with young children | Medium to large | Sturdy enough to handle play; gentle giants |
Frequently Asked Questions
How do I know what size my dog will be?
The most reliable indicator is breed. For purebreds, check the AKC or UKC breed standard for the official weight and height range. For mixed breeds, use the puppy weight formulas above or get a DNA test, which will identify dominant breeds and give a size prediction based on breed composition.
Do dog paw size predict adult size?
Paw size is a rough indicator — puppies with large paws relative to their body often grow into large adults. However, it is not a reliable formula. The puppy weight-at-age formulas are significantly more accurate for size prediction.
When is a dog fully grown?
Toy and small breeds reach adult size at 9–12 months. Medium breeds finish growing at 12–15 months. Large breeds are typically done at 15–18 months. Giant breeds (Great Danes, Mastiffs, Saint Bernards) may continue growing until 18–24 months, though weight may continue to increase through 3 years as they fill out.
What is the biggest dog breed?
The English Mastiff holds the record for heaviest dog breed, with males regularly exceeding 200 lb. The Great Dane holds the record for tallest, with some males standing over 32 inches at the withers. The Irish Wolfhound is considered the tallest breed by standard, reaching up to 35 inches.