How old is an 18-year-old dog in human years?
An 18-year-old dog is about 88–135 in human years, depending on size: 88 for small dogs, 95 for medium dogs, 111 for large dogs and 135 for giant dogs. Few dogs of any size live this long.
At 18 years, a dog is
95 human years
Vet chart (by size)
No breed or size picked, so we assumed a medium-sized dog.
This is older than the typical lifespan, so treat the number as a rough estimate.
Other methods: DNA formula (UCSD study): 77 · The ×7 rule: 126
The default is the size-based vet chart. See how pet age is calculated.
Dog ages around 18
| Dog age | Small | Medium | Large | Giant |
|---|---|---|---|---|
| 15 years | 76 | 83 | 93 | 114 |
| 16 years | 80 | 87 | 99 | 121 |
| 17 years | 84 | 91 | 105 | 128 |
| 18 years | 88 | 95 | 111 | 135 |
| 19 years | 92 | 99 | 117 | 142 |
| 20 years | 96 | 103 | 123 | 149 |
The default is the size-based vet chart. See how pet age is calculated.
18-year-old dog by breed
FAQ
How old is an 18-year-old dog in human years?
An 18-year-old dog is about 88–135 in human years, depending on size: 88 for small dogs, 95 for medium dogs, 111 for large dogs and 135 for giant dogs. Few dogs of any size live this long.
Is an 18-year-old dog old?
It depends on size. At 18, dogs of every size are seniors. Vets consider a dog a senior in the last quarter of its expected lifespan.
How old is an 18-year-old dog with the ×7 rule?
126, compared with 95 on the vet chart for a medium dog. The ×7 rule is a myth: pets age fast in their first two years and more slowly after that.