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Dog Age Calculator

Convert your dog's age to human years by breed size.

Privacy: your files never leave your device. All processing happens locally in your browser.

How to use

  1. 1.Enter your dog's age in years — use a decimal like 0.5 for a puppy of about 6 months.
  2. 2.Choose your dog's adult size: Small, Medium, Large, or Giant (by weight).
  3. 3.Read the equivalent human age instantly below, with the AKC chart result and an epigenetic-clock comparison.

About Dog Age Calculator

This dog age calculator converts dog years to human years the moment you type, using the American Kennel Club and American Veterinary Medical Association size-based chart rather than the myth that one dog year equals seven human years. Enter your dog's age in years, pick its adult size, and the human-age equivalent appears instantly, with no button to press.

The old "multiply by 7" rule is wrong. It has circulated since the 1950s but has no scientific basis: it was likely a marketing rule of thumb, reverse-engineered from the idea that humans live to about 70 and dogs to about 10. Dogs do not age at a steady 7-to-1 pace. They mature very fast early, then slow down, so a 1-year-old dog is not "7" but closer to a 15-year-old human who has already reached physical maturity, and a 2-year-old dog is around 24. After that, each dog year adds roughly 4 to 6 human years depending on size.

Size is the biggest factor this tool accounts for. Small dogs (20 lbs or less) live longest and age slowly, so a 10-year-old small dog is about 56 in human years. Medium dogs (21 to 50 lbs) are close behind at about 60. Large dogs (51 to 100 lbs) reach about 66, and giant breeds (100 lbs and up) age fastest of all: a 10-year-old giant is about 79 human years, and giants even start ahead, counting a 1-year-old as 12 rather than 15 but overtaking the others by age 3. This is why a Great Dane is considered a senior years before a Chihuahua of the same age.

The numbers here come straight from the AKC's published dog-age chart, which follows AVMA guidance: 15 human years for the first year, about 9 more for the second (24 total), then a size-dependent amount each year after. Whole-year ages match the chart exactly; fractional ages are interpolated and ages past 16 are extrapolated, so a 6-month puppy or a rare 18-year-old still gets a sensible estimate.

As a second opinion the tool also shows the 2020 epigenetic-clock estimate, human_age = 16 x ln(dog_age) + 31, published by Wang and colleagues in Cell Systems at UC San Diego. That formula is based on DNA-methylation "aging" measured in Labrador Retrievers, ignores body size, and applies from age 1, so it can differ from the size chart; both are shown as estimates, not precise ages.

Everything runs in your browser. Nothing about your dog is uploaded or stored, there is no signup, and you can run as many conversions as you like. To estimate a cat's age instead, use the cat age calculator; to work out a person's exact age from a birth date, use the age calculator; and to count the days between two dates, use the date difference calculator.

Frequently asked questions

Is 1 dog year really 7 human years?
No. The "multiply by 7" rule is a myth with no scientific basis; it has circulated since the 1950s but does not reflect how dogs actually age. Dogs mature fast in their first two years — roughly 15 human years by age 1 and 24 by age 2 — then age about 4 to 6 human years per year depending on size. This calculator uses the AKC/AVMA chart instead of the times-7 shortcut.
How do I convert dog years to human years accurately?
Use a size-based chart. Enter your dog's age and pick its adult size (Small, Medium, Large, or Giant). The tool applies the AKC's vet-backed figures: 15 human years for year one, 24 by year two, then a size-dependent amount each year after, since smaller dogs age more slowly than giant breeds.
Why does my dog's size change the result?
Larger dogs age faster and have shorter lifespans, so size strongly affects the human-age equivalent after the first couple of years. For example, a 10-year-old small dog is about 56 in human years, a medium about 60, a large about 66, and a giant breed about 79. That is why a Great Dane becomes a senior years before a small terrier of the same age.
How old is my puppy in human years?
Puppies mature fastest in their first year, reaching about 15 human years by age 1 (12 for giant breeds). For an age under 1, enter a decimal such as 0.5 for roughly 6 months. The tool gives a linear approximation of that first year, but real puppy development is front-loaded, so a very young pup may be slightly "older" than the straight-line estimate suggests.
What is the epigenetic-clock dog age formula?
It is a 2020 method from Wang and colleagues (Cell Systems, UC San Diego) based on DNA-methylation aging in Labrador Retrievers: human_age = 16 x ln(dog_age) + 31. It ignores body size and applies from age 1, so it can differ from the AKC size chart. This tool shows it as a second-opinion comparison; treat both figures as estimates, not exact ages.

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