How old is a 21-month-old puppy in human years?
≈ 22 human years.
Fully grown and settling into adult behaviour patterns.
Breed size hardly matters yet. A dog's first two years run on the same fast schedule whatever the breed — the first year is worth about 15 human years, the second about nine more. Only after age two do small and giant breeds start to diverge, and then quickly.
Nearby ages
| 18 months | 20 human years |
|---|---|
| 21 months | 22 human years |
Related
Age shown for a 21-month-old dog of average breed size.