Dog Age Calculator
Convert a dog's age into an approximate human-equivalent age.
Quick answer: enter your details below and click Calculate Dog Age — your result appears instantly, right here in your browser. Nothing you enter is uploaded or stored.
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How to use
- Enter the dog's age in years.
- Choose the dog's size.
- Click Calculate Dog Age for the human-equivalent estimate.
About this tool
Enter a dog's age in years and its size, and the tool estimates a human-equivalent age: the first year counts as 15 human years, the second adds 9, and each later year adds 5 for a medium dog (4 for small, 6 for large). This is a rough guide, not a veterinary assessment — breed and health matter more than any single formula.
Frequently asked questions
Do large dogs age faster?
Yes, later in life. That is why large dogs add 6 per year after year two here, against 4 for small dogs.
Is this a veterinary assessment?
No. It is a rough guide. For health decisions, ask a vet who knows the dog.