Race Predictor Calculator
Predict your running times for any distance using Riegel's proven formula
Predict Your Race Time
Distance of your most recent race result
Hours
Minutes
Seconds
Distance you want to predict the time for
Race Time Predictions
Example Calculation
Recent Race Result
Distance: Half Marathon (21.1 km)
Time: 1:57:26
Performance: Good level runner
Prediction for 30K
Formula: T₂ = 7046 × (30/21.1)^1.06
T₂ = 7046 × 1.4225^1.06
T₂ = 7046 × 1.463
Predicted Time: 2:43:08
Formula Assumptions
You've done appropriate training for the target distance
No significant natural tendency for speed or endurance
Less accurate for times under 3.5 minutes
Less accurate for times over 4 hours
Adjusted for distance - not a simple linear scaling
Race Preparation
Nutrition: Proper diet and hydration strategy
Recovery: Don't race when fatigued from training
Mental preparation: Stay stress-free and focused
Warm-up: Gradually prepare muscles and cardiovascular system
Training specificity: Train for your target distance
Understanding Race Prediction
Riegel's Formula Explained
Peter Riegel's race prediction formula, published in 1977 in Runner's World, uses the mathematical relationship T₂ = T₁ × (D₂/D₁)^1.06 to predict race times based on previous performance at a different distance.
The 1.06 Exponent
The 1.06 exponent accounts for the physiological reality that running performance doesn't scale linearly with distance. As distance increases, pace typically slows due to fatigue accumulation and energy system limitations.
Formula Accuracy
- •Most accurate for distances between 1 mile and marathon
- •Works best for trained runners with consistent training
- •Assumes appropriate training for target distance
Training Considerations
Distance-Specific Training
- 5K-10K: Speed work, VO₂ max intervals
- 15K-Half Marathon: Tempo runs, lactate threshold
- Marathon: Long runs, aerobic base building
- Ultra: Endurance, mental toughness, fueling
Using Predictions
- Goal Setting: Set realistic race time goals
- Pacing Strategy: Plan your race pace splits
- Training Zones: Calculate training paces
- Race Selection: Choose appropriate distances