Health & Nutrition
Science-backed fitness and nutrition calculators that respect your privacy. Every tool uses peer-reviewed formulas — Mifflin-St Jeor for calories, Karvonen for heart rate zones, US Navy method for body fat — the same equations used by dietitians, trainers, and sports scientists. Your weight, measurements, and health data never leave your browser. No app, no account, no tracking — just accurate numbers to guide your training and nutrition.
Calories & Nutrition
Weight & Body Composition
Training & Performance
Lifestyle
Frequently Asked Questions
Are these fitness calculators medically accurate?
All tools use peer-reviewed formulas: Mifflin-St Jeor for BMR/TDEE, US Navy method for body fat, Karvonen for heart rate zones, and Epley/Brzycki for one-rep max. These are the same equations used by dietitians, trainers, and sports medicine professionals. However, individual results vary — use them as guidelines, not medical advice.
Is my health data private?
Completely. Your weight, body measurements, fitness data, and health information never leave your browser. There is no account, no cloud storage, and no tracking. Zero data is transmitted to any server.
Should I consult a doctor before using these tools?
These calculators provide general fitness estimates, not medical diagnoses. If you have health conditions, are pregnant, or are starting a new exercise program, consult a healthcare professional before making changes based on calculator results.