Find out how old your dog really is in human years — based on their breed size, not the outdated "×7" rule.
Editorially ReviewedYour dog's life stage helps you understand what to expect — from puppy energy to senior care needs.
Life-stage care guides, new calculators, and seasonal reminders — one email a week.
The science behind dog-to-human age conversion.
Large dogs age faster than small ones — here's why.
Puppy, adult, senior — what to expect at each stage.
More calculators for your dog's daily care.
You've probably heard that "1 dog year = 7 human years." That's a myth — and it underestimates how fast dogs mature in their first two years, while overestimating later ones. Modern veterinary science uses size-adjusted formulas based on the AVMA (American Veterinary Medical Association) and AAHA Life Stage Guidelines.
Here's a quick reference for how your dog's age compares to human years, by breed size:
| Dog Age | Small (≤20 lb) | Medium (21–50 lb) | Large (51–90 lb) | Giant (>90 lb) |
|---|---|---|---|---|
| 1 year | 15 | 15 | 14 | 12 |
| 2 years | 24 | 24 | 23 | 21 |
| 5 years | 36 | 39 | 41 | 42 |
| 8 years | 48 | 54 | 59 | 63 |
| 10 years | 56 | 64 | 71 | 77 |
| 13 years | 68 | 79 | 89 | 98 |
| 15 years | 76 | 89 | 101 | 112 |
We base our calculation on three life phases:
Large and giant breeds reach physical maturity around the same time as smaller breeds, but they age more rapidly afterward. A 10-year-old Great Dane is biologically closer to a 75-year-old human, while a 10-year-old Chihuahua is closer to 56.
No — that rule is a myth. Dogs mature much faster than humans in their first two years (a 1-year-old dog is biologically closer to a 15-year-old human), and the aging rate slows down afterward and varies by size.
Small dogs age more slowly than giant breeds. The size-adjusted formula used by MyNubs reflects current veterinary science.
Large and giant breeds reach physical maturity around the same time as small dogs, but their cells continue to grow and metabolize faster, leading to earlier onset of age-related conditions.
A Great Dane is considered senior at about 6 years old, while a Chihuahua isn't considered senior until 10 or 11.
Average lifespan varies significantly by size and breed:
Small breeds (under 20 lb) typically live 12-16 years. Medium breeds live 10-14 years. Large breeds live 9-12 years. Giant breeds (over 90 lb) often live only 7-10 years.
Individual dogs vary based on genetics, weight, and preventive care.
Veterinary senior care typically begins at:
10-11 years for small dogs, 8-10 years for medium dogs, 6-8 years for large dogs, and 5-6 years for giant breeds.
Senior status means twice-yearly vet visits are recommended, along with senior-specific diet considerations and screening for age-related conditions.
The biggest factor is maintaining a lean body weight — overweight dogs live an average of 2 years less than dogs at ideal weight.
Other proven factors: regular preventive vet care, dental hygiene, daily exercise appropriate for their age, mental stimulation, and avoiding common toxins (chocolate, xylitol, grapes, certain medications).