Dog age calculator

See your dog’s age in human years, as a range by size, and the life stage they’re in.

Sources last checked Nov 7, 2026. Not veterinary advice.

Your dog

From 8 weeks (about 2 months) to 25 years.

Size Adult weight in lb

Not sure? Medium is the default.

More options Adult weight

Optional. If you know it, we place your dog in a size class from it.

In human years

Enter your dog’s age or birth date to see the range.

Not veterinary advice. PupRange gives estimates from published veterinary sources. Every dog is different. If you’re worried, call your veterinarian.

Good to know

  • Regular checkups let your vet spot age changes early. Ask how often your dog should come in.

Why “dog years × 7” is wrong

The times-7 rule assumes dogs age at the same pace their whole life. They don’t. The AVMA guideline, as quoted by the American Kennel Club, counts a dog’s first year as about 15 human years and the second as about 9 more. After that, a medium-size dog adds roughly 5 human years per year, and bigger dogs age faster than smaller ones.

A 2020 study from UC San Diego (Wang et al., Cell Systems) compared age-related DNA changes in Labrador Retrievers and people. It found the same pattern: very fast aging early, then a slower pace. Its formula is human age = 16 × ln(dog age) + 31. At 1 year that already gives about 31, well past 7.

Neither method is perfect, and they don’t agree, so we show the span between them instead of picking one number.

A 2-year-old dog is about 24 in human years by the AVMA rule the AKC quotes and about 42 by the 2020 DNA-methylation formula from Labrador data, not 14 as the “times 7” rule says.

How it’s calculated

We run two published methods on the same age and show the range between them.

  1. Size-adjusted vet rule. Following the AVMA guideline as quoted by the AKC: 15 human years for the first year, 9 more for the second, then about 5 per year for a medium dog. For toy, small, large and giant dogs we scale that yearly step by typical lifespan for the size class (Montoya et al. 2023), so a dog with a shorter expected life ages faster. That scaling is our estimate. Before age 1 we spread the 15 years evenly across the year, which is also our estimate.
  2. DNA-methylation clock. Human age = 16 × ln(dog age in years) + 31 (Wang et al. 2020). It was built on Labrador Retrievers and isn’t defined before about 8 weeks, which is why the calculator starts there.
  3. Most likely value. From age 1 we use the size rule, because it accounts for size. Before age 1 we use the DNA clock, because the size rule has only one number for the whole first year.
  4. Life stage. The 2019 AAHA guidelines call the last 25% of expected lifespan senior. We apply that to the Montoya life expectancy for each size class. Young adult runs to age 4; puppyhood ends at about 12 months for toy to medium dogs and 18 months for large and giant dogs, in line with VCA’s growth guidance. These cut-offs are our thresholds.

If you pick a breed, its AKC adult weight sets the size class. If you enter an adult weight, we use that instead of the size you picked.

Sources

  1. Wang T, Ma J, Hogan AN, et al. Quantitative translation of dog-to-human aging by conserved remodeling of the DNA methylome Cell Systems 11(2):176–185 (UC San Diego news release), 2020. Checked
  2. American Kennel Club, How to Calculate Dog Years to Human Years (quotes the AVMA guideline; updated Sep 14, 2026) Checked
  3. Creevy KE, Grady J, Little SE, et al. 2019 AAHA Canine Life Stage Guidelines JAAHA 55:267–290, 2019. Checked
  4. Montoya M, Morrison JA, Arrignon F, et al. Life expectancy tables for dogs and cats derived from clinical data Frontiers in Veterinary Science 10:1082102, 2023. Checked
  5. VCA Animal Hospitals and Canadian Academy of Veterinary Nutrition, Feeding Growing Puppies (updated Feb 4, 2025) Checked

Questions owners ask

Is 1 dog year really 7 human years?

No. The AVMA guideline, as quoted by the American Kennel Club, counts the first year as about 15 human years and the second as about 9 more, then adds roughly 5 a year for a medium-size dog. A 2020 UC San Diego study of DNA changes in Labrador Retrievers also found that dogs age fastest early in life and more slowly later, which a flat times-7 rule can’t show.

Why do small dogs live longer?

Across breeds, bigger dogs tend to have shorter lives. A 2023 study of clinic records (Montoya et al.) found an average life expectancy of about 13.4 years for toy and 13.5 for small breeds, but about 9.5 years for giant breeds. The AKC quotes one estimate that every 4.4 lb of body mass lowers life expectancy by about a month.

When is a dog considered a senior?

Definitions differ. The 2019 AAHA life stage guidelines call a dog senior in the last 25% of its expected lifespan, so it depends on size. The AVMA guideline, as quoted by the AKC, says small dogs are seniors at around 7 and larger breeds at 5 to 6. Our calculator uses the AAHA definition with life expectancy by size, which gives a later senior age, so it’s worth asking your vet about senior checkups either way.

Does the DNA clock work for all breeds?

Not yet. The 2020 DNA-methylation study that gave the formula human age = 16 × ln(dog age) + 31 looked only at Labrador Retrievers. That’s why we show it next to the size-adjusted vet rule instead of on its own.

How long do dogs live by size?

In the 2023 Montoya study, average life expectancy was about 13.4 years for toy breeds, 13.5 for small, 12.7 for medium, 11.5 for large and 9.5 for giant breeds. These are averages across many dogs; your dog’s health, weight and care matter as much as size.

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