Dog Age Calculator
Convert your dog's age to human years with the modern formula: first year ≈ 15 human years, then 9, and about 4 per year after that. Weekly updates.
About this tool
This dog age calculator uses the modern vet-approved conversion: the first year of a dog's life equals about 15 human years, the second adds 9 more, and each year after that adds about 4 (5 for large breeds).
Science has replaced the old multiply-by-seven myth. Understanding your dog's real age helps you track senior-care milestones like joint health, dental checks and diet changes — the calculator gives you the honest number plus a size-adjusted estimate.
FAQ
Why is the old "7x" rule wrong?
Dogs mature much faster in the first two years — roughly 24 human years by age two. The old one-size rule overestimates young dogs and underestimates seniors.
Which dogs live longer?
Small breeds typically live 12–16 years, large breeds 8–12. Small dogs hit senior milestones later in calendar time.
How old is a one-year-old dog?
About 15 human years. A two-year-old dog is about 24, and each additional year adds roughly 4–5.