Based on your current pace using the Riegel formula
5K
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10K
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Half Marathon
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Marathon
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Training Zone Recommendations
Easy/Recovery
--:-- - --:--
60-70% effort. Conversational pace.
Aerobic/Endurance
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70-80% effort. Steady breathing.
Tempo/Threshold
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80-90% effort. Comfortably hard.
Interval/VO2max
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90-100% effort. Hard breathing.
Note: Race predictions use the Riegel formula (T2 = T1 x (D2/D1)^1.06) and assume equivalent training and race-day conditions. Individual results may vary based on training, terrain, weather, and other factors.
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Understanding Running Pace and Race Predictions
Running pace is the foundation of every training plan and race strategy. Whether you're training for your first 5K or aiming for a marathon PR, understanding your pace helps you train smarter and race better.
What is Running Pace?
Running pace is typically expressed as the time it takes to cover one mile or one kilometer. For example, an 8:00 per mile pace means you complete each mile in 8 minutes. This metric helps runners maintain consistent effort throughout their run and plan race strategies effectively.
How Race Predictions Work
This calculator uses the Riegel formula, developed by researcher Peter Riegel in the 1970s. The formula accounts for the fact that running speed decreases predictably as race distance increases due to physiological factors like glycogen depletion and fatigue.
The formula is: T2 = T1 x (D2/D1)^1.06, where T1 is your known time, D1 is your known distance, D2 is the target distance, and T2 is the predicted time.
Understanding Training Zones
Easy/Recovery (60-70% effort): The majority of your training should be at this pace. It builds aerobic base while allowing for recovery.
Aerobic/Endurance (70-80% effort): Long run pace that builds stamina and teaches your body to burn fat efficiently.
Tempo/Threshold (80-90% effort): Comfortably hard pace that improves lactate threshold and mental toughness.
Interval/VO2max (90-100% effort): High-intensity efforts that improve speed and running economy.
Tips for Using Split Times
Split times help you maintain even pacing throughout your race. Most successful races are run with even or slightly negative splits (second half faster than first). Use the split times as a guide, but also listen to your body and adjust based on how you feel, terrain, and weather conditions.
