Race Time & Pace Predictor
Predict your finish times, split paces, and Daniels aerobic training zones for 5K, 10K, Half Marathon, and Full Marathon.
Base 5K pace: 4:54 min/km (7:53 min/mi). Marathon split: 5:39 min/km.
Predicted Race Times & Equivalent Paces Chart
Calculated across all standard distances using Pete Riegel's 1.06 power-law model:
| Race Event | Distance | Predicted Time | Pace (min/km) | Pace (min/mile) |
|---|
Frequently Asked Questions
How does the Pete Riegel race prediction formula work?
Published in American Scientist (1977) by engineer Pete Riegel, the formula T2 = T1 × (D2 / D1)^1.06 models the aerodynamic and metabolic fatigue curve of human endurance. The 1.06 exponent accounts for glycogen depletion and cardiovascular drift over longer distances.
Why might my actual marathon time be slower than the 5K prediction?
The Riegel formula assumes you have completed appropriate aerobic volume and long runs for the target distance. If you have only trained for a 5K, muscular endurance and glycogen depletion (the 'marathon wall' at mile 20) will cause greater slowdown unless weekly mileage is sufficient.
What is the best base distance to predict a marathon time?
A recent Half Marathon or 10-Mile race provides the most accurate predictor for a Full Marathon because its metabolic energy pathway is closer to the marathon demands than a 1-mile or 5K sprint.
What are Daniels' VDOT training zones?
Dr. Jack Daniels established training intensities based on race velocity: Easy/Long Run pace (~65–79% HRmax), Marathon pace (~80–85% HRmax), Threshold/Tempo pace (~88–92% HRmax), and Interval pace (~98–100% VO2max).
Scientific References
- Riegel PS. (1977). Athletic records and human endurance. American Scientist, 65(3), 285–290.
- Daniels J. (2013). Daniels' Running Formula (3rd ed.). Champaign, IL: Human Kinetics.
