Cat Years to Human Years is a web based calculator that estimates a cat’s age in human years. Users can enter a known age from one month to 25 years and view the estimated equivalent, including estimates for kitten months. The tool also supports reverse conversion and provides an age chart and visual comparison across life stages. The calculator uses reference points in which a cat’s first year is approximately 15 human years, the second birthday is about 24, and each additional cat year adds about four human years. Values are rounded to one decimal place, and kitten ages between reference points are estimated. The site notes that these figures are comparisons rather than precise biological measurements and that individual cats vary. A typical workflow is to enter or select a cat’s age, review the calculated human age, and consult the chart for context. The site also lists feline life stage references from FelineVMA and AAHA/AAFP, and provides an email contact for feedback or calculation reports. The supplied information does not specify any particular device or software requirements.