Dog Age Calculator

Convert your dog’s age to human years using the size-based chart method, with the 2020 epigenetic clock for reference. Calculates in your browser.

Roughly equivalent human age

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Epigenetic estimate (2020 clock)-
Life stage-

Show the math

Dogs mature fast then level off, and bigger dogs age quicker. The human age comes from the American Kennel Club's size chart for dogs aged 1 to 16: the first year is about 15 human years (12 for giant breeds) and the second reaches about 24 (22 for giant breeds), after which larger dogs pull ahead. Part years are read between the chart's whole years, and ages past 16 continue at the chart's last yearly step.

The epigenetic estimate uses the 2020 DNA-methylation clock, 16 × ln(years) + 31, derived from Labrador Retrievers. It is shown from one to 16 years old: the curve drops below zero for young puppies, and the dogs it was fitted on were up to 16.

Life stages follow the 2019 AAHA Canine Life Stage Guidelines: puppy until rapid growth stops (about 6–9 months), young adult until physical and social maturity (most dogs by 3–4 years), then mature adult, and senior for the last 25% of the breed's expected lifespan.

These are population averages, individual dogs vary by breed and health. Everything is calculated in your browser.

What this does

A dog age calculator converts your dog’s age to human years using the size-based chart method, with the 2020 epigenetic clock for reference.

How to use it

  1. Enter your dog’s age.
  2. Choose the size or breed band.
  3. Read the human-year equivalent.
  4. See the life stage.

How it works

Dogs mature fastest in year one (≈ 15 human years, 12 for giant breeds), then larger breeds age quicker later. The human age is read from the American Kennel Club’s size chart; the 2020 epigenetic clock, fitted on Labrador retrievers, is shown alongside from one year old. Both improve on the old "7 years" rule; treat the result as a guide.

human years = AKC size-chart value, read between whole years (epigenetic clock: 16 × ln(dog age) + 31)

Understanding your result

The result is a guide, not a fixed equivalence, because dogs age fastest in the first year and larger breeds then age quicker than small ones. The size-based chart and the 2020 epigenetic clock both improve on the old seven-year rule, so use the figure to gauge life stage rather than an exact human age.

Example

A 2-year-old medium dog is roughly 24 human years.

Sources & methodology

Last updated .

Frequently asked questions

Is one dog year really seven human years?

No — that old rule is too rough. Dogs mature fastest early on (year one ≈ 15 human years) and larger breeds age quicker later, which this calculator accounts for.

Why does size matter?

Small dogs live longer and age more slowly after maturity, while giant breeds age fastest, so the human-equivalent years added per year differ by size.

How is the life stage worked out?

From the 2019 AAHA Canine Life Stage Guidelines: puppy until rapid growth stops (about 6–9 months), young adult until physical and social maturity (most dogs by 3–4 years), then mature adult. A dog is a senior in the last 25% of its breed’s expected lifespan, which varies by breed and size, so the calculator says so rather than guessing a single age.

Is anything stored?

No. Everything is calculated locally in your browser.