Convert a cat’s age into human years

As with dogs, the first two years weigh more. Here: 15, then 9, then 4 human years per year. A 3-year-old cat is 15+9+4 = 28. No breed split. This is not a life expectancy.

1 year → 15

2 years → 24

n>2 → 24 + (n−2) × 4

A common feline teaching chart, distinct from the canine one (which varies by size). No single source “validates” a human-age figure: it is a metaphor for pace, not physiology.

Cat’s age

Current age in years. 0.5 = six months.

Assumptions

• 15 / 9 / 4 chart.
• No breed.
• An honest age entry.

Limits

• No disease or spay/neuter status.
• No life expectancy.
• Not a veterinary opinion.

Useful for explaining that a two-year-old cat is no longer a kitten. Useless for dosing a dewormer: follow weight and the label, or the veterinarian.

• Multiplying by 7.

  The first two years are denser.

• Using the dog chart.

  After two years a cat gains 4 human years, not 5 or 6.

• Reading a prognosis.

  The number does not describe health.

• Dog ageAge and size. The tool applies a stepped chart, not the “times seven” rule.
• Age calculatorThe age shown is civil: completed years, then months, then leftover days. It is not the number of days divided by 365.25. An empty “Age on” field means today.
• Pregnancy due dateOne date: the first day of the last period. The tool adds 280 days for the due date and 14 days for a model conception.

Written by Rédaction HexaCalc (editorial team). Content last updated: August 25, 2026. No third-party medical or financial review is claimed.

This calculation uses a standard mathematical identity. See also the methodology.