Interactive Tools
The runner's toolbox
Interactive running tools and calculators to compute training paces, heart rate zones, race predictions, and age-graded performances.
Pace Calculator
Free online running pace calculator — instantly calculate your target pace, estimated finish time, or distance for 5K, 10K, half marathon, and marathon. Built into Apex Run.
Race Predictor
Apex Run's race predictor automatically forecasts your 5K, 10K, half marathon, and marathon finish times using Riegel's Formula calibrated to your last 6 weeks of real training data — no manual input required.
Heart Rate Zones Calculator
Free online running heart rate zones calculator. Instantly calculate your 5 training zones using Max HR, Karvonen (HRR), or Lactate Threshold (LTHR) methods. Perfect for configuring custom zones in Apex Run.
VDOT Calculator
Free online Jack Daniels VDOT calculator. Instantly estimate your VDOT score, calculate Easy (E), Marathon (M), Threshold (T), Interval (I), and Repetition (R) training paces, and predict equivalent race times.
Age-Grading Calculator
Free road running age-grading calculator based on official WMA standards. Find your age-graded percentage score, prime-age equivalent finish time, and master runner level for 5K, 10K, Half Marathon, and Marathon.