Calendar calculation scope
Results follow the Gregorian calendar and the method described on the page. They measure calendar dates and do not account for an individual's time of birth, historical local calendars or an organisation's age-attainment rules. Check inputs and the required convention before relying on a result.
Pet age comparisons
Cat and dog human-year equivalents illustrate a general age chart. They do not measure an animal's biological age, diagnose health or predict its lifespan. Breed, size and individual factors matter. A veterinarian can assess the animal directly.
Content and sources
Guides explain the calculations and link relevant sources where a comparison or cultural rule is discussed. A source can be updated independently. Send corrections through our contact page.