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 chart method counts the first year as about 15 human years, the second as 9 more, then a size-based amount each year after:

human = 24 + (years − 2) × per-year

Per-year is 4 (small), 5 (medium), 6 (large) or 7 (giant). The epigenetic estimate uses the 2020 DNA-methylation clock, 16 × ln(years) + 31, derived from Labrador Retrievers.

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), then larger breeds age quicker later. The size chart and the 2020 epigenetic clock both improve on the old "7 years" rule; treat the result as a guide.

human years ≈ 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.

Is anything stored?

No. Everything is calculated locally in your browser.