Step 1: Your Recent Reference Run / Race
Enter a recent completed race or hard training run to establish your baseline running fitness.
Step 2: Target Race Information
Define your goal race distance, course profile and expected environmental conditions.
Important Athletic & Medical Disclaimer
This Race Time Predictor uses general endurance‑sport mathematical models only. It does not account for all individual physiological variables, race‑specific hazards, or certified coaching advice. This tool is not medical guidance. Always consult a certified running coach or medical professional before undertaking strenuous endurance events.
How Race Time Prediction Works (Peter Riegel Formula Basis)
The core formula used: T₂ = T₁ × (D₂ / D₁)^1.06
Where T₁ = known time, D₁ = known distance, D₂ = target distance, T₂ = predicted time. We then apply modifiers for elevation gain, terrain type, temperature and humidity to produce conservative, target and optimistic finish‑time scenarios.
Race Time Prediction FAQ
How accurate is the Riegel formula for long‑distance races?
The Riegel formula provides a theoretical baseline. For marathon and ultra‑distance events, fatigue accumulation, fueling, mental stress and race day variables create larger deviations from predicted times.
Why do elevation and heat change predicted finish times?
Elevation gain increases muscular workload and oxygen demand. High temperature and humidity reduce cooling efficiency, increasing perceived exertion and risk of performance drop‑off.
What is the difference between conservative, target and optimistic predictions?
Conservative accounts for typical race‑day fatigue and sub‑optimal conditions. Target is the expected realistic performance with good execution. Optimistic assumes perfect fueling, pacing and race‑day conditions.
Can I use trail run data to predict a road marathon?
Terrain differences create large performance gaps. Trail performance predictions for road races require careful terrain adjustment and are less reliable than same‑surface comparisons.