Precision Calculators

Evidence-based tools for pace analysis, race prediction, and training zone optimization.

Long Run Calculator
Calculate your optimal long run distance (20% of weekly mileage)

For easy pace guidance

Why 20%?

The 20% rule balances endurance adaptation with injury prevention. Running one long run at 20% of your weekly volume builds aerobic capacity without overloading connective tissue. This ratio is backed by research showing runners who exceed 30% of weekly mileage in a single run face significantly higher injury rates.

Long Run Benefits

  • Aerobic base: Increases mitochondrial density and capillary development
  • Mental toughness: Builds confidence to sustain effort
  • Fat adaptation: Teaches body to use fat as fuel
  • Running economy: Improves efficiency at target paces

Progression Tips

  • Increase weekly mileage by no more than 10% per week
  • Allow 3-4 weeks of adaptation before increasing long run distance
  • Every 4th week, reduce long run by 20-30% for recovery
  • If weekly mileage changes, recalculate long run distance accordingly
Training Zone Calculator
Calculate your VDOT and training paces
Pace Calculator
Calculate your running pace from distance and time
Race Time Predictor
Predict race times using the Riegel Formula