Pet to human age calculator

Pick your companion's species, enter both birth dates, and discover the day your ages meet - with animal-to-human age conversion.

How to read this pet-to-human age equivalence chart

Converting a cat or dog's age into human years helps you place your companion's life stages: growth, adulthood, then senior years. A 1-year-old cat is already like a young adult, while dogs age faster or slower depending on size - small breeds generally live longer than giant breeds.

The chart below converts an animal's calendar age (from 1 to 16 years) into approximate human years for cats and four dog sizes (small, medium, large, giant). Use it as a quick reference, then the calculator above to find the day your ages actually meet.

Age equivalence chart

Animal calendar age converted to human years, by species and size.

Approximate values based on popular formulas.
Animal age	Cat	Dog
Animal age	Cat	Small	Medium	Large	Giant
1 year	15 years	15 years	15 years	15 years	12 years
2 years	24 years	24 years	24 years	24 years	22 years
3 years	28 years	28 years	29 years	30 years	29 years
4 years	32 years	32 years	34 years	36 years	36 years
5 years	36 years	36 years	39 years	42 years	43 years
6 years	40 years	40 years	44 years	48 years	50 years
7 years	44 years	44 years	49 years	54 years	57 years
8 years	48 years	48 years	54 years	60 years	64 years
9 years	52 years	52 years	59 years	66 years	71 years
10 years	56 years	56 years	64 years	72 years	78 years
11 years	60 years	60 years	69 years	78 years	85 years
12 years	64 years	64 years	74 years	84 years	92 years
13 years	68 years	68 years	79 years	90 years	99 years
14 years	72 years	72 years	84 years	96 years	106 years
15 years	76 years	76 years	89 years	102 years	113 years
16 years	80 years	80 years	94 years	108 years	120 years

Why cat and dog human-age equivalents aren't linear

Popular equivalence formulas speed up the early years (very fast growth) then slow down. That's why a kitten or puppy "gains" many human years in the first year, then progresses more gently afterward. For dogs, size matters: a giant dog ages faster than a small-breed dog.

These conversions remain playful approximations, not veterinary diagnoses. They help you understand your pet's relative age, anticipate needs, and share a fun moment: the shared birthday when you and your companion are the same age. For a personalized estimate, go back to the calculator at the top with both dates of birth.