Running Pace Calculator
Pace ↔ speed ↔ race time
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minutes per km
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Pace per km
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Pace per mile
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Speed (km/h)
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Speed (mph)
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5K predicted
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10K predicted
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Half-marathon predicted
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Marathon predicted
Predictions use Riegel's formula
T₂ = T₁ × (D₂ / D₁)^1.06. Trained runners match within 2-3%; beginners typically go 5-10% slower at longer distances because the fatigue factor isn't fully captured. Use the prediction as floor, not goal.
Related tools
Pace benchmarks for amateur runners
- Beginner 5K: 7:30 – 8:30 min/km
- Recreational: 5:30 – 7:00 min/km typical training pace
- Sub-25 5K: 5:00 min/km
- Sub-4 marathon: 5:41 min/km sustained
- Boston qualifier (M <35): 3:00 marathon = 4:16 min/km
Heat penalty: every +5°C above ~10°C slows you ~1-2% per km for races. Most Indian road races run 18-30°C — expect your prediction to look \"fast\" vs what you can actually run on race day.