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Animal Age In Human Years Calculator

Work out animal age in human years instantly with clear inputs, formula shown and shareable results.

About Animal Age In Human Years Calculator

Uses the 2020 epigenetic clock formula for dogs, adjusted for adult size, and the standard stepped feline scale for cats.

Formula

Age conversion

Dogs: human age = 16 x ln(dog age) + 31. Cats: 15 human years for the first year, 9 for the second, then 4 for each additional year

Worked example

With the default values below, Animal Age In Human Years Calculator returns Equivalent human age of 56.8. Change any input above and every figure here is recalculated in your browser.

Inputs used

Speciesone of Dog, Cat
Dog
Ageaccepts 0.1–30 years
5 years
Adult size (dogs)one of Small under 10 kg, Medium 10 to 25 kg, Large over 25 kg
Medium 10 to 25 kg

Results

Equivalent human age
56.8 years
Life stage
Adult
Human years per animal year
11.35
Method used
Epigenetic clock formula 16 x ln(age) + 31, adjusted for adult size

Step by step

  1. 1Values used
  2. 2Age conversion
  3. 3Equivalent human age= 56.8 years
  4. 4Life stage= Adult
  5. 5Human years per animal year= 11.35
  6. 6Method used= Epigenetic clock formula 16 x ln(age) + 31, adjusted for adult size

Assumptions and limits

  • The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why is the dog formula logarithmic?

Methylation comparisons show dogs age very fast early and then far more slowly, which a logarithm captures better than a flat multiplier.

Does size really matter?

Yes. Large breeds age faster and have shorter lifespans, which the size adjustment approximates.

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