🏃Running & Endurance
Calculators for runners and endurance athletes: pace and splits, race-time prediction, VO2 max, heart-rate training zones, and calories burned.
Pace Calculator
Enter any two of distance, time, and pace — get the third instantly, plus per-km and per-mile splits.
Race Time Predictor
Enter a recent race result and target distance to estimate your finish time using the proven Riegel formula.
VO2 Max Calculator
Estimate your VO2 max from a race distance and time using the Daniels–Gilbert model.
Calories Burned Running
Estimate how many calories you burn on a run based on your weight, pace, and duration.
Heart Rate Zone Calculator
Find your five personal heart-rate training zones using your age (or measured max HR) and resting heart rate.