16 years in dog years is about 87 human years
A 16-year-old dog is about 87 in human years if it is medium-sized (21 to 50 lb), on AVMA’s chart. A small dog of the same age is about 80, a large one 101 and a giant one 129. The DNA clock of a 2020 study gives 75.4.
16 years in human years, by size
| Size | Human years | Life stage (AAHA) | Senior from (VCA) |
|---|---|---|---|
| Small (20 lb or less) | 80 | Senior | 11 years |
| Medium (21 to 50 lb) | 87 | Senior | 10 years |
| Large (51 to 100 lb) | 101 | Senior | 8 years |
| Giant (over 100 lb) | 129 | Senior | 7 years |
Dog age calculator, with 16 years filled in: change the size, or work a human age back to dog years.
The end of the AVMA chart
AVMA’s chart stops at 16, at 87 human years for a medium dog, and the oldest dogs in the study of Wang et al. were 16 too. Past this page, the calculator carries the charts on to 20 years, the end of Merck’s table.
Seven times 16 is 112, 25 human years more than AVMA’s chart: the old rule ends up furthest from the chart for the oldest dogs, the other way round from where it began.
What changes from 15 to 16
This birthday adds 4 for a small dog, 4 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 1.0.
Life stage at 16
Dogs of every size are seniors at 16, 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 16.
What the DNA clock says about a 16-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 16 years that is 75.4 human years, 11.6 fewer than the 87 of AVMA’s chart for a medium dog.
At 16, the chart of every size reads at least the clock: the clock slows down in later life, while the charts keep adding several human years a year.
The seven-year rule at this age
Seven times 16 is 112. The chart puts a 16-year-old dog between 80 and 129 human years by size, and the medium dog at 87, so the rule is 25 human years too high for a medium dog. No veterinary source on this page uses it.
Frequently asked questions
How old is a 16-year-old dog in human years?
About 80 for a small dog (20 lb or less), 87 for a medium dog (21 to 50 lb), 101 for a large dog (51 to 100 lb) and 129 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 16-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.
Other ages in dog years
Dog age chart: every age and size in one table · Dog age calculator
Sources
- AVMA, Pets age faster than people (chart for a medium-sized dog of 21 to 50 lb)
- Merck Veterinary Manual, Description of Dogs (Antinoff, reviewed October 2026), Dog years versus human years
- PetMD, How Old Is My Dog in Human Years? (Coates, DVM, December 2024)
- Wang T, et al. Quantitative Translation of Dog-to-Human Aging by Conserved Remodeling of the DNA Methylome. Cell Systems 2020;11(2):176–185
- The same study, free full text on PubMed Central (PMC7484147)
- 2019 AAHA Canine Life Stage Guidelines (Creevy et al., JAAHA 2019;55:267–290), Table 1
- VCA Animal Hospitals, How Old is Old? Comparing Dog Age to Human Age (Weir, Llera, Buzhardt)