Dog Age Calculator: Dog Years to Human Years
"Multiply by 7" is a myth. Vets convert dog years using size-adjusted charts, because after maturity a Chihuahua gains ~4 human years per year while a Great Dane gains ~7.
How the conversion works
The vet-consensus method: a dog's first year ≈ 15 human years, the second adds ~9 (a 2-year-old dog ≈ 24), and every year after that adds 4–7 human years depending on size. Size is the variable the 7-year rule ignores, and it's the one that matters most.
| Dog years | Small (<20 lb) | Medium (20–50) | Large (51–90) | Giant (90+) |
|---|---|---|---|---|
| 1 | 15 | 15 | 15 | 15 |
| 2 | 24 | 24 | 24 | 24 |
| 3 | 28 | 28 | 30 | 31 |
| 5 | 36 | 36 | 40 | 45 |
| 7 | 44 | 47 | 50 | 56 |
| 10 | 56 | 60 | 66 | 79 |
| 13 | 68 | 74 | 82 | 100 |
| 16 | 80 | 87 | 99 | 121 |
Dog age conversion, year by year
The same chart the calculator uses, written out for quick reference. Small means under 20 lb, medium 20 to 50, large 51 to 90, giant over 90.
How old is a 1 year old dog in human years?
A 1 year old dog of any size is about 15 in human years. Every size lands at 15 here, the fastest year of a dog's life.
How old is a 2 year old dog in human years?
A 2 year old dog of any size is about 24 in human years. All sizes converge again at 24. From here the paths split by size.
How old is a 3 year old dog in human years?
About 28 human years for a small breed, 28 for a medium, 30 for a large breed and 31 for a giant.
How old is a 4 year old dog in human years?
About 32 human years for a small breed, 32 for a medium, 35 for a large breed and 38 for a giant.
How old is a 5 year old dog in human years?
About 36 human years for a small breed, 36 for a medium, 40 for a large breed and 45 for a giant.
How old is a 6 year old dog in human years?
About 40 human years for a small breed, 42 for a medium, 45 for a large breed and 49 for a giant.
How old is a 7 year old dog in human years?
About 44 human years for a small breed, 47 for a medium, 50 for a large breed and 56 for a giant. A giant breed at 7 is entering its senior years while a small dog is comfortably middle aged.
How old is a 8 year old dog in human years?
About 48 human years for a small breed, 51 for a medium, 55 for a large breed and 64 for a giant.
How old is a 9 year old dog in human years?
About 52 human years for a small breed, 56 for a medium, 61 for a large breed and 71 for a giant.
How old is a 10 year old dog in human years?
About 56 human years for a small breed, 60 for a medium, 66 for a large breed and 79 for a giant. This is where the size gap becomes stark. Nearly 80 for a giant breed, mid 50s for a small one.
How old is a 11 year old dog in human years?
About 60 human years for a small breed, 65 for a medium, 72 for a large breed and 86 for a giant.
How old is a 12 year old dog in human years?
About 64 human years for a small breed, 69 for a medium, 77 for a large breed and 93 for a giant.
How old is a 13 year old dog in human years?
About 68 human years for a small breed, 74 for a medium, 82 for a large breed and 100 for a giant. A giant breed reaching 13 has passed the century mark in human terms, a genuinely rare achievement.
How old is a 14 year old dog in human years?
About 72 human years for a small breed, 78 for a medium, 88 for a large breed and 107 for a giant.
How old is a 15 year old dog in human years?
About 76 human years for a small breed, 83 for a medium, 93 for a large breed and 114 for a giant.
How old is a 16 year old dog in human years?
About 80 human years for a small breed, 87 for a medium, 99 for a large breed and 121 for a giant. Few giants reach 16. For small breeds it maps to a solid 80, a long life well lived.
Dog age FAQ
Is the "7 dog years" rule accurate?
No. It's wrong at both ends: a 1-year-old dog is like a 15-year-old human (not 7), and after maturity the per-year rate depends on size, ~4 human years for small dogs, ~7 for giants. It survives because it's easy to remember.
Why do big dogs age faster?
Faster growth, earlier cellular wear, shorter lifespans. A Great Dane is geriatric at 7; a Chihuahua at 7 is middle-aged. Across mammals bigger species live longer: within dogs, selective breeding flipped the rule.
When is my dog a senior?
AAHA pegs "senior" at the last quarter of expected lifespan: roughly 10–11+ for small dogs, 8–10 for medium, 7–8 for large, 6–7 for giant breeds. Twice-yearly exams and screening bloodwork are the standard senior upgrades.
How long will my dog live?
Typical ranges: small breeds 12–16 years, medium 10–14, large 9–12, giant 7–10. Weight control is the single biggest owner-controlled lever: lean-fed dogs in lifetime studies lived ~2 years longer than overweight littermates.
Senior dogs = rising vet bills, and premiums rise with age too
Insurance only covers what isn't pre-existing. If you're going to insure, the math says do it while your dog is young. See real 2026 prices by provider.
Compare pet insurance prices →Related dog calculators
Sources: AAHA Canine Life Stage Guidelines; veterinary consensus size-adjusted aging tables (AKC/AVMA-aligned); breed lifespan ranges from breed-club published figures cross-checked against UK VetCompass life tables (Teng et al. 2022, Scientific Reports). Personality lines are affectionate breed stereotypes, not veterinary assessments. Last reviewed August 2026.