Pet Age Calculator: Dog and Cat Age Comparison
Compare dog or cat age with a transparent human-age approximation. Adjust the later-year multiplier for a dog instead of using a universal seven-year rule.
Your inputs
Choose the units and assumptions that match your data. Example inputs are illustrative.
Your result
Enter your values, then choose Calculate.
Results are calculated in your browser. Display rounding does not change the underlying calculation.
Calculation breakdown
Method, assumptions and worked example
How it works
This simplified model assigns 15 comparison years to year one and nine more to year two. Later cat years add four each. Later dog years use the entered multiplier. Fractional ages are linearly interpolated within each segment. These conventions describe the arithmetic, not a validated biological clock.
Worked example
A five-year-old cat gives 24 + (5 − 2) × 4 = 36 comparison years. A five-year-old dog using multiplier 5 gives 39.
Using the result
Breed, body size, health and individual variation matter, especially for dogs. This comparison does not set screening schedules, define a precise senior threshold or forecast life expectancy. Use actual age and veterinary advice for care decisions.
Frequently asked questions
Is multiplying age by seven accurate?
It misses the faster early maturation and differences between animals.
Why is the dog multiplier adjustable?
No single multiplier fits all breeds. Adjustability makes the assumption visible rather than implying a universal conversion.
Method review and references
Formula and content reviewed on 10 October 2026. Worked examples are hypothetical. Methods and assumptions are explained on each page. Health estimates are not clinical measurements; symbolic tools are for entertainment.