These are estimates only. Predicted times can differ from actual race results due to many factors not captured by the model.
Predictions use the Daniels VDOT model. Your known race result is used to calculate a VDOT score — a measure of your current running fitness — which is then used to predict equivalent performances at other distances.
The fitness level setting adjusts how well you are assumed to sustain effort over longer distances, reflecting differences in aerobic endurance between recreational and elite runners.
Factors not accounted for include course profile, weather, pacing strategy, race-day nutrition, and individual strengths at specific distances.
Heart rate estimate
This is a rough estimate only. Individual heart rates vary significantly and the actual value during a run can differ substantially from this prediction.
The estimate uses the ACSM running equation to calculate oxygen demand from your pace and elevation gain, then converts that to a heart rate using your age (to estimate maximum HR) and fitness level (to estimate resting HR and VO₂max).
Factors not accounted for include heat, humidity, fatigue, hydration, terrain variability, and individual cardiovascular differences.