Dog Age Calculator

Multiplying by seven makes a one-year-old dog seven, when it is already closer to a human of thirty.

Human-equivalent age56.8 years

Life stageAdult

Actual age5 years

What the old times-seven rule would say35 yearsout by 21.8 years here

Size categoryMediumat 20 kg

Typical lifespan for this size10 to 14 years

Proportion of an average life41.7%

A year from now59.7 human yearsa gain of 2.9

This is the 2020 methylation clock, built by comparing chemical marks on dog and human DNA. It fits far better than multiplying by seven, but it was derived largely from Labradors and does not account for the size effect separately.

The formula

human years = 16 * ln(dog years) + 31

The "multiply by seven" rule is simply wrong

It makes a one-year-old dog the equivalent of a seven-year-old child, when in fact that dog is sexually mature and close to a human of thirty. The 2020 methylation clock — comparing chemical marks on dog and human DNA — gives 16 × ln(age) + 31 instead, and that curve rises steeply early then flattens, which is what actually happens.

Big dogs age faster

Across species, larger animals live longer. Within dogs the relationship reverses: a Great Dane is elderly at seven while a small terrier is barely middle-aged. Why domestic dogs invert the usual pattern so sharply remains genuinely unexplained, and it is one of the reasons dogs are studied so heavily in the biology of ageing.

This does not replace a veterinarian

Every figure on this page comes from a published reference range, and a range is what it stays. The right dose for an individual animal depends on its kidney and liver function, on what else it is taking, on whether it is pregnant or very young or very old, and on what is actually wrong with it — none of which arithmetic can see. Use this to understand the scale of a dose or an exposure, and to have a better conversation with your vet. Do not use it to start, stop or change a medication.

If you believe your animal has swallowed something toxic, do not wait to see whether signs develop. Contact your veterinarian or an animal poison line immediately — in most poisonings the treatment that works is the one given early.