Precision calculators for runners, cyclists, and health enthusiasts — powered by validated algorithms (AHA, PhenoAge, Karvonen, Cycling Power Model).
Calculate running pace, finish time, or distance. Get race predictions for 5K, 10K, half marathon, and full marathon based on your performance.
Estimate power from speed or speed from power using aerodynamic and rolling resistance models. Includes rider weight for accuracy.
Smart BMI and BMR calculator. Body fat analysis, calorie burn estimate, and healthy weight range. Free, no ads, mobile ready.
Estimates true physiological age using RHR, sleep, daily steps, exercise frequency, and smoking status. NHANES-based mortality risk.
Compare your RHR against age and sex-specific fitness percentiles. See where you rank — from athlete to poor.
Personalized 5-zone training ranges. Choose Heart Rate Reserve (HRR) or classic formula to optimize endurance, fat burn & VO₂max.