Dog Age Calculator

Enter your dog's age in years and months to see the human-equivalent age, life stage, and expected lifespan.

AVMA aging factors differ by size — large and giant dogs age faster after age five.

Enter your pet's age above to see results.

Aging Timeline

How the dog age formula works

This calculator uses the AVMA standard formula: the first year of a dog's life counts as roughly 15 human years, the second year adds 9 more (total 24), and each year after that adds about 5 human years for a medium-size dog. Small breeds age slightly slower; large and giant breeds age faster — Sprint 2 will let you choose breed and size.

Why know your dog's human age?

Understanding your dog's human-equivalent age helps you plan vet visits, adjust diet for life stage, and notice signs of aging early. Puppies need vaccinations and socialization, adult dogs need regular exercise and dental care, and senior dogs benefit from twice-yearly check-ups and joint support.

Reference Table

Quick lookup for dog age in human years across all 4 size categories using AVMA standard.

Pet age (years) Small (<10kg) Medium (10-25kg) Large (25-45kg) Giant (>45kg)
1 15 15 15 15
2 24 24 24 24
3 28 29 30 31
4 32 34 36 38
5 36 39 42 45
6 40 44 48 52
7 44 49 54 59
8 48 54 60 66
9 52 59 66 73
10 56 64 72 80
11 60 69 78 87
12 64 74 84 94
13 68 79 90 101
14 72 84 96 108
15 76 89 102 115
16 80 94 108 122
17 84 99 114 129
18 88 104 120 136
19 92 109 126 143
20 96 114 132 150

Values shown are based on AVMA standard formula. Individual dogs may age faster or slower depending on breed genetics, diet, and health.

Sources & Citations

All formulas and life stage data are sourced from peer-reviewed veterinary publications and professional veterinary associations.

This calculator is for educational and informational purposes only. Always consult a licensed veterinarian for medical advice specific to your pet.

FAQ

How is dog age converted to human years?

The AVMA standard formula treats the first year as roughly 15 human years and the second year as 9 more (total 24). After year two, each dog year adds about 5 human years for a medium-size dog. So a 5-year-old medium dog is approximately 39 in human years.

What are the dog life stages?

Dog life stages are puppy (under 1 year), junior (1–2), adult (3–6), senior (7–10), and geriatric (11+). Larger breeds age faster, so a giant-breed dog may reach senior status closer to year 5.

How long do dogs live?

Average lifespan depends on size: small dogs (under 9kg) live around 14 years, medium dogs about 12, large dogs about 11, and giant breeds around 8. Sprint 1 of this calculator uses the medium-size default; Sprint 2 will add explicit breed and size selectors.