1. What is the McMillan Race Pace Calculator?

The McMillan Race Pace Calculator predicts race times for different distances based on your performance at a reference distance. It uses a power-law relationship that accounts for the non-linear relationship between distance and running time.

2. How Does the Calculator Work?

The calculator uses the McMillan prediction formula:

Where:

• \( T_{new} \) — Predicted time for new distance (minutes)
• \( T_{ref} \) — Known time for reference distance (minutes)
• \( D_{new} \) — New target distance (miles or km)
• \( D_{ref} \) — Reference distance (miles or km)
• \( k \) — Exponent (typically ≈1.06)

Explanation: The formula accounts for the fact that running pace slows non-linearly as race distance increases.

3. Importance of Race Prediction

Details: Accurate race prediction helps runners set appropriate pace goals, plan training, and avoid starting too fast in longer races.

4. Using the Calculator

Tips: Enter your recent race time and distance, the new target distance, and the exponent (k). Use recent race results for best accuracy. The default k=1.06 works well for most runners.

5. Frequently Asked Questions (FAQ)

Q1: What's the best reference distance to use?
A: Use a recent race result that's closest to your target distance for most accurate predictions.

Q2: Why does k≈1.06?
A: Research shows this exponent best describes the relationship between distance and time for most runners.

Q3: How accurate are these predictions?
A: Predictions are generally within 2-3% of actual performance for well-trained runners.

Q4: Should I adjust k for different distances?
A: Advanced runners may use slightly different exponents for short vs long distances (1.07-1.08 for short, 1.05-1.06 for long).

Q5: Does this account for terrain or weather?
A: No, predictions assume similar conditions. Adjust expectations for hills, heat, or altitude.