Dog & Cat Years Calculator
Enter an age in human years and see the equivalent age for a cat and for dogs of four different sizes, all at once.
Frequently asked questions
Is this tool free?
Yes. Calchemy tools are free to use in your browser.
Is my data uploaded?
No. The tools are designed to run locally in your browser unless clearly stated otherwise.
Why does dog size matter?
Smaller dog breeds tend to age more slowly in their later years than large and giant breeds, so this tool uses a different curve for small, medium, large and giant dogs rather than one flat multiplier - that's why entering one human age shows a different dog age for each size.
Is the old 'multiply by 7' rule accurate?
No - it's a popular myth. Both dogs and cats age much faster in their first two years and then more steadily afterwards, which is why this tool uses a curve instead of a flat multiplier.
Is this vet-grade accurate?
No, it's an approximation for fun based on commonly published pet-age charts. Ask your vet for anything that actually matters for your pet's care.