Rat Terrier Age Calculator
Convert your Rat Terrier's age to human years, adjusted for small-breed aging. Life expectancy 12–18 years.
Last reviewed July 2026 · Free · Nothing you enter is stored
small breed
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Educational estimate for a small breed. Individual dogs vary — your vet is the best judge of your Rat Terrier's life stage.
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About Rat Terrier aging
The Rat Terrier is a small breed with a typical adult weight of 10–25 lbs and a life expectancy of 12–18 years. Because aging speed tracks body size, this page uses the small-breed rate — the slowest, which is why small dogs often reach 15+.
Frequently asked questions
How do you calculate a Rat Terrier's age in human years?
As a small breed, the Rat Terrier ages at the small-breed rate: about 15 human years in year one, 24 by age two, then roughly 4 human years for each dog year after that. Enter an age above to see the exact figure alongside the UCSD epigenetic estimate.
How long do Rat Terriers live?
The typical Rat Terrier life expectancy is 12–18 years. Keeping your dog at a healthy weight, staying current on veterinary care, and dental hygiene are the biggest levers on the high end of that range.
When is a Rat Terrier considered a senior?
Smaller breeds like the Rat Terrier typically enter their senior years around age 8–10. Senior care means more frequent vet checks and often a diet adjustment.
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