Dogs and cats mature much faster than humans. The first year is roughly equivalent to 15 human years, and the second year adds about 9 more, so a 2-year-old pet is about 24 in human years. After that, dogs age about 5 human years per year, while cats age about 4 per year. This calculator uses that standard conversion to estimate your pet's human age.
Small and large breeds age at different rates, but the common estimate adds 5 human years per year for dogs and 4 for cats after age 3. Cats are generally considered to age a little more slowly than dogs. Actual health depends on breed, weight, and environment, so regular veterinary checkups matter.
Converting to human years makes it easy to grasp your pet's life stage. From around age 7 (about 44+ human years), pets enter their senior stage and need more attention to joint health, dental care, and weight management. Providing age-appropriate food and exercise helps extend a healthy lifespan.