Dog Age and Cat Age in Human Years Calculator
Choose a dog or cat, the dog's adult size and its age in years. Dogs get two estimates, the epigenetic clock formula and a size-based table; cats use the standard table. All results are estimates.
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Formula
- Dog, 2020 epigenetic clock (Wang et al., preprint 2019):
human age = 16 × ln(dog age) + 31 - Size table (dogs): year 1 = 15, year 2 = 24, then +4 (small), +5 (medium) or +6 (large) per year.
- Cat table: year 1 = 15, year 2 = 24, then +4 per year.
These are estimates. Individual animals and breeds age differently, and the formula is meant for ages from about 3 months up.
Worked example
A 7 year old medium dog:
- Formula: ln 7 = 1.9459, so 16 × 1.9459 + 31 = 62.1 human years.
- Table: 24 + 5 × (7 − 2) = 49 human years.
A 10 year old cat: 24 + 4 × 8 = 56 human years.
Frequently asked questions
How do I convert dog years to human years?
Use human age = 16 × ln(dog age) + 31, from the 2020 epigenetic clock (Wang et al., preprint 2019). For a 7 year old dog, ln 7 = 1.946, so 16 × 1.946 + 31 = 62.1 human years.
Is the 7 dog years to 1 human year rule true?
No. Dogs mature very fast in their first years and then age more slowly. A 1 year old dog is closer to a 30 year old person than to a 7 year old child.
How old is a cat in human years?
The usual table gives 15 years for the first year, 24 for the second and 4 more for each year after. A 10 year old cat is 24 + 8 × 4 = 56 human years.
How does dog size change the result?
In the size table every year after the second adds 4 human years for a small dog, 5 for a medium one and 6 for a large one, because bigger dogs tend to age faster. A 7 year old dog is 44, 49 or 54 on that table.