Dog Size Calculator
Find your dog’s size category and predict adult weight
Current Weight (lbs)
Age
Puppy Age (weeks, if puppy)
Dog Size Categories Explained
Dog size affects everything — from food requirements to life expectancy to aging rate. Our dog size calculator identifies your dog’s size category and provides breed-appropriate care guidance.
Dog Size Guide
| Size | Weight | Life Expectancy | Senior Age |
|---|---|---|---|
| Toy | Under 10 lbs | 12-16 years | 10-12 yrs |
| Small | 10-20 lbs | 12-15 years | 10-12 yrs |
| Medium | 20-50 lbs | 10-13 years | 8-10 yrs |
| Large | 50-90 lbs | 8-12 years | 7-8 yrs |
| Giant | 90+ lbs | 6-10 years | 5-6 yrs |
FAQs
What size is a 40 lb dog?
A 40 lb dog falls into the medium size category. Examples include Border Collies, Cocker Spaniels, and Australian Shepherds at this weight.
How do I predict my puppy’s adult size?
The most reliable estimate: double your puppy’s weight at 4 months. For large breeds, multiply 16-week weight by 2.5. Use the calculator above for a quick estimate, and our dog age calculator to track life stage milestones.
Conclusion
Our dog size calculator gives you instant size categorisation and breed-specific care guidance. Pair it with our dog food calculator for size-appropriate daily portions and our weight calculator for health monitoring.