About Petcalc101

Petcalc101 builds free calculators for dog and cat owners: age in human years, how much to feed, and pregnancy due dates.

Our principles

• Sources shown. Every formula comes from a published veterinary guideline or study, and each page links to it.
• Honest about limits. Pets vary. We label results as estimates and explain what each one leaves out. See how we calculate.
• Private. Calculations run in your browser. We never see or store what you type.
• Kept current. Formulas and tables were last reviewed on 2026-11-11.

The site is free to use and supported by advertising. Spotted an error? Let us know and we will fix it.