A 11-year-old Whippet in human years

Whippet at 11 years

69human years

medium breed — senior, roughly 85% through a typical lifespan

AVMA size-based15 for year one, 9 for year two, then 5/year for a medium breed	69human years
Epigenetic clock16 × ln(age) + 31 — Wang et al. 2020, calibrated on Labradors	69human years
Difference between the twothe two methods agree closely at this age	+0years
Life stage	senior
Size class25–40 lb — larger dogs age faster	medium
Typical lifespanmedian for medium breeds	13years
Share of life so far	85%
Typical years remaininga population median, not a prediction about your dog	2years

Breed: Whippet
Age: 11 years

Two answers, and neither is simply wrong

69 human years by the AVMA size-based table: 15 for the first year, 9 for the second, then 5 a year for a medium breed.

69 human years by the epigenetic clock published in Cell Systems in 2020 — human age = 16 × ln(dog age) + 31, derived from DNA methylation.

They differ by 0 years here. The epigenetic clock is a measurement rather than a convention and captures early life remarkably well, but it was calibrated on Labradors and cannot see breed size. The AVMA table does account for size but is a smoothed consensus.

Bigger dogs age faster

This is backwards from mammals in general, and it is why no single conversion works. A medium breed adds about 5 human years per dog year after the second birthday; a small breed adds 4, a giant breed 6.5.

The old "multiply by seven" rule gets a one-year-old badly wrong in one direction and a fifteen-year-old badly wrong in the other.

Where this dog is

Life stage: senior. Roughly 85% through a typical lifespan for a medium breed, with a median of 13 years.

Those are population medians from veterinary data, not a forecast — individual dogs of every size routinely live well past them.

The one thing that moves the number

Weight. A landmark Purina lifetime study found dogs kept lean lived about 1.8 years longer than littermates fed 25% more. That is a larger effect than almost anything else within your control.

Notes

Bigger dogs age faster, which is backwards from mammals in general and is the reason no single conversion table works. A medium breed adds about 5 human years per dog year after the second birthday; a small breed adds 4, a giant breed 6.5. The old "multiply by seven" rule gets a one-year-old badly wrong in one direction and a fifteen-year-old badly wrong in the other.
The two methods land within 0 years of each other here, which is about as close as they get.
At senior stage, twice-yearly vet visits are the standard recommendation rather than annual ones. Most of what shortens a senior dog's remaining time — dental disease, arthritis, kidney and heart changes — is manageable when found early and expensive when found late.
Lifespan figures are population medians from veterinary data, not a forecast. Individual dogs of every size routinely live well past them.

Nearby sizes

French Bulldog Harnesses: Why the Chart Almost Always Reads SmallThe French Bulldog is the breed weight-based charts get most wrong, because almost none of its measurements are where the weight suggests they should be.
Measuring a Dog for a Harness: Three Numbers, Ninety SecondsGirth sizes the harness. Neck decides whether it goes on. Almost every returned harness is one of four measuring errors rather than a bad chart.
No-Pull Harness Sizing: Why Fit Decides Whether It Works at AllA front-clip harness is the one style where fit is not a comfort question. Half an inch of slack and the mechanism it depends on simply stops happening.
Puppy Harness Sizing: Why Age Is the Worst Index of AllAge tells you less about a puppy's chest than any other variable, because two puppies of the same age can be six months apart in development and four sizes apart in girth.