Male runner checking body weight on a digital scale at an outdoor track at night

Weight & Pace Impact Calculator

See How Body Weight Changes Affect Your Performance

Curious how dropping (or gaining) a few pounds will impact your next race? Enter your details to predict exactly how your running or cycling paces will shift—and get expert coaching tips to optimize your results.

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Body Weight & Pace Impact Calculator - Performance Predictions
Weight & Pace Impact Calculator

Discover how body weight changes affect your running and cycling performance with science-based predictions.

Body Weight
Current Running Pace
-10%
Downhill
0%
Flat
+5% +10%
Steep
+15% +20%
Very Steep
How Weight Affects Performance

The Science Behind Weight & Performance:

  • Running: Every 1% of body weight lost ≈ 1% faster on flat terrain
  • Moderate hills (5-10%): Weight loss has 2-3x greater impact
  • Steep climbs (10-20%): Weight loss has 3-5x greater impact
  • Cycling: Power-to-weight ratio is king, especially on hills
  • Flat cycling: Aerodynamics matter more than weight

Real-World Examples:

  • 8-10%: Typical mountain road (Alpe d'Huez average)
  • 12-15%: Steep climbs (Mortirolo, Angliru sections)
  • 15-20%: Very steep (Zoncolan, Canton Avenue)

Important Considerations:

  • Predictions assume fitness level remains constant
  • Rapid weight loss can decrease power and endurance
  • Optimal race weight varies by individual
  • Focus on sustainable, gradual changes

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Body Weight & Race Performance

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