13 years in dog years is about 74 human years

13 years in human years, by size

Dog age calculator, with 13 years filled in: change the size, or work a human age back to dog years.

The medium chart passes the DNA clock

Merck’s table lists 13 to 14 dog years as 68 to 72 human years. AVMA’s chart gives a 13-year-old medium dog 74, and the DNA clock 72.0: from this year on, the medium chart reads older than the clock.

The giant line is now past 100 human years. Few giant dogs reach 13, and the figure shows how fast a giant dog ages more than an age a person reaches.

What changes from 12 to 13

This birthday adds 4 for a small dog, 5 for a medium dog, 5.5 for a large dog and 7.5 for a giant dog in human years on the chart. The DNA clock adds 1.3.

Life stage at 13

Dogs of every size are seniors at 13, by the stages of the 2019 AAHA guidelines and the senior ages of VCA (small 11, medium 10, large 8, giant 7).

No size turns senior at exactly 13.

What the DNA clock says about a 13-year-old dog

Wang et al. (Cell Systems, 2020) matched the DNA methylation of 104 Labrador retrievers with that of people and fitted human age = 16 × ln(dog age) + 31. For 13 years that is 72.0 human years, 2.0 fewer than the 74 of AVMA’s chart for a medium dog.

At 13, the chart reads older than the clock for medium, large and giant dogs and younger for small dogs: the clock slows down with age while the bigger sizes keep a steep line.

The seven-year rule at this age

Seven times 13 is 91. The chart puts a 13-year-old dog between 68 and 106.5 human years by size, and the medium dog at 74, so the rule is 17 human years too high for a medium dog. No veterinary source on this page uses it.

Frequently asked questions

How old is a 13-year-old dog in human years?

About 68 for a small dog (20 lb or less), 74 for a medium dog (21 to 50 lb), 84.5 for a large dog (51 to 100 lb) and 106.5 for a giant dog (over 100 lb), on the charts of AVMA, Merck and PetMD. Your veterinarian can tell you where your own dog is.

Is a 13-year-old dog a senior?

Yes, whatever its size: VCA counts dogs as seniors from 7 (giant) to 11 or 12 (small). AAHA defines a senior as a dog in the last 25% of its expected life and suggests exams at least every six months.