TRANSLATING DOG YEARS to human equivalents isn’t as easy as it used to be, but it’s more accurate.

The old “multiply by seven” method doesn’t reflect the pace at which dogs progress through life stages like infancy, puberty and adulthood. A 1-year-old dog that already has borne puppies is not the equivalent of a 7-year-old child.

In 2020, researchers developed a better biological clock based on the way genes are switched on and off during development and aging. They compared these so-called epigenetic changes in dogs of various ages to those in humans.

The result suggests a 1-year-old dog is equivalent to a 30-year-old person. At 4, a dog is at about the same stage as a human who’s 50. After that, the rate of dog aging slows in comparison to humans.

Here’s the conversion formula the scientists came up with: Human age is equal to 16 multiplied by the natural logarithm of the dog’s age, plus 31. (To get the natural logarithm, enter the dog’s age on a calculator and hit the “LN” button.)

If that’s too intimidating, here’s a cheat sheet (with approximate LN numbers):
Dog age           Human age
2 (LN 0.693)         42 (16 x .693 + 31)
9 (LN 2.197)         66 (16 x 2.197 + 31)
12 (LN 2.485)       71 (16 x 2.485 + 31)
18 (LN 2.890)       77 (16 x 2.89 + 31)