CatCalc.online is a free collection of practical calculators for cat owners. Our goal is simple: give you clear, science-informed estimates for age conversion, feeding, weight management and breeding timelines — without ads that interrupt or data collection that tracks you.
What we calculate
- Cat age from birth date → human-year equivalent
- Cat years ↔ human years (size-adjusted AVMA method + UCSD epigenetic formula)
- Next birthday and life stage (kitten / adult / senior / geriatric)
- Daily calories (RER & MER), weight-loss targets, water intake
- Ideal weight from Body Condition Score, rough kitten adult-weight projection
- Pregnancy due dates, heat-cycle estimates
Our formulas
Age conversion uses the widely cited size-adjusted approach (first year ≈ 15 human years, second ≈ +9, then 4–7 years per Cat year by size) and the UCSD 2020 logarithmic formula (16 × ln(cat age) + 31). Calorie estimates follow the standard veterinary RER = 70 × (kg)0.75 model. Pregnancy windows reflect typical 58–68 day feline gestation.
Important disclaimer
These tools provide educational estimates only. They are not a substitute for professional veterinary diagnosis, nutrition planning or reproductive care. Always consult a licensed veterinarian for decisions about your cat’s health.