CALCULATOR · Pets
Dog Age Calculator
Convert dog years to human years with the UCSD epigenetic formula or a size-based breed estimate.
Show formula
Inputs
Labels the result — it does not change the number
Result
Your result appears here
Enter Age (years) and the result fills in as you type.
How it works
- Type your dog's name and pick the breed if you want them shown — neither changes the result.
- Enter the dog's age in years and months.
- Read the human-equivalent estimate and life stage.
Frequently asked questions
Which formula converts dog years to human years?
One formula, for every dog: the UC San Diego epigenetic clock published in Cell Systems in July 2020, human age ≈ 16·ln(dog age) + 31. It was derived by comparing DNA-methylation patterns in 104 Labrador retrievers against 320 human methylomes.
Why does the classic "multiply by seven" rule give a different answer?
Because dogs do most of their ageing early. The seven-times rule is a flat multiplier with no research behind it; the logarithmic curve puts a one-year-old at about 31 human years and a seven-year-old at about 62, which matches how the biology actually behaves.
Why does changing the breed not change the number?
Because no published formula converts breed into a human-equivalent age. Larger breeds are known to age faster after maturity, but the size charts that put a number on it have no cohort, no methodology and no peer review, so this tool does not use one. The breed you pick labels the result and nothing more.
Why is there no result for a very young puppy?
The formula returns no valid value below roughly eight weeks — mathematically it crosses zero at about 7.5 weeks and goes negative beneath that. Rather than substitute an invented curve, the tool reports the life stage and no number.
Is the result scientifically exact?
No conversion between dog and human ageing is exact, and the study behind this one used a single breed. Treat every number here as a central estimate that varies by individual animal.
Examples
- How old is a 7-year-old dog in human years?
- About 62. That is the headline figure from the 2020 study, and it is close to the old seven-times answer by coincidence rather than agreement — the two diverge sharply everywhere else.
- And a 1-year-old dog?
- About 31. The first year covers the fastest development, which is why the curve is so steep at the start and flattens later.
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