How do I calculate my dog's age in human years?

The 'multiply by 7' rule is outdated. Modern veterinary science shows dogs age rapidly in their first two years (15 human years in year 1, 9 in year 2), then 4-7 human years per dog year depending on breed size.

Do small dogs really live longer than large dogs?

Yes. Small breed dogs (under 20 lbs) age more slowly after year 2 and often live 12-16 years. Giant breeds (over 90 lbs) age faster and typically live 7-10 years. This is reflected in our breed-specific calculator.

Dog Age Calculator

Convert your dog's age to human years using breed-specific veterinary formulas. Stop using the outdated "multiply by 7" rule — modern science shows that dogs age at different rates depending on their size.

🐕 Enter Your Dog's Details

Dog's Age (years)

Enter decimal for partial years (e.g., 1.5 for 1 year and 6 months)

Breed Size

Dog Age to Human Years — Quick Reference

See how dog years translate to human years at a glance across all breed sizes.

Dog Age	Small Breed (<20 lbs)	Medium Breed (21-50 lbs)	Large Breed (51-90 lbs)	Giant Breed (>90 lbs)
1 year	15	15	15	15
2 years	24	24	24	24
3 years	28	29	30	31
5 years	36	39	42	45
7 years	44	49	54	59
10 years	56	64	72	80
12 years	64	74	84	94
15 years	76	89	102	115

Frequently Asked Questions

Our calculator uses the latest veterinary aging models based on DNA methylation (epigenetic clock) research published by UC San Diego and other institutions. The formula accounts for the fact that dogs age rapidly in their first two years, then the rate varies dramatically by breed size. While it's the most accurate method available to the public, individual dogs may age differently based on genetics, diet, exercise, and healthcare.

The "1 dog year = 7 human years" rule assumes a linear aging curve, but dogs age non-linearly. They reach sexual maturity around 1 year (equivalent to about 15 human years), and large breeds age significantly faster after year 2. A 10-year-old Chihuahua is roughly 56 in human years, while a 10-year-old Great Dane is closer to 80. Using the "×7" rule would give both as 70 — which is inaccurate for both.

Dogs generally go through these life stages: Puppy (0-1 year) — rapid growth and development; Adolescent (1-2 years) — physical maturity, behavioral development; Adult (2-7 years for most breeds) — prime years; Senior (varies by breed: small breeds 10+, medium 8+, large 6+, giant 5+) — increased health monitoring needed; Geriatric (upper end of breed lifespan) — may need specialized care.