Half Marathon Conversion Chart

Race Time Conversion Formula:

\[ T_{new} = T_{ref} \times \left(\frac{D_{new}}{D_{ref}}\right)^k \]

Reference Time (T_ref):

minutes

Reference Distance (D_ref):

New Distance (D_new):

km (21.0975 = half marathon)

Exponent (k):

(typically 1.06)

Predicted Time (T_new):

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1. What is the Race Time Conversion Formula?

The race time conversion formula estimates your potential race time at one distance based on your performance at another distance. It's particularly useful for predicting half marathon times based on shorter race performances.

2. How Does the Calculator Work?

The calculator uses the following formula:

\[ T_{new} = T_{ref} \times \left(\frac{D_{new}}{D_{ref}}\right)^k \]

Where:

\( T_{new} \) — Predicted time for new distance (minutes)
\( T_{ref} \) — Your time for reference distance (minutes)
\( D_{new} \) — New distance (km)
\( D_{ref} \) — Reference distance (km)
\( k \) — Exponent (typically 1.06 for endurance running)

Explanation: The formula accounts for the fact that running speed decreases non-linearly as distance increases.

3. Importance of Race Time Prediction

Details: Accurate race time prediction helps runners set appropriate pace goals, plan training programs, and estimate finish times for races they haven't run before.

4. Using the Calculator

Tips: For best results, use recent race times (within last 3 months) for distances between 5km and 10km to predict half marathon times. The default exponent (k=1.06) works well for most runners.

5. Frequently Asked Questions (FAQ)

Q1: Why is the exponent typically 1.06?
A: Research shows this value best represents how running performance scales with distance for most trained runners.

Q2: How accurate are these predictions?
A: Predictions are generally within ±3% for runners with consistent training, but may be less accurate for beginners or those specializing in very short/long distances.

Q3: Can I use this for ultra-marathon predictions?
A: The formula becomes less accurate for distances beyond marathon (42.2km). Ultra-running requires different physiological adaptations.

Q4: Why does my predicted time seem too fast/slow?
A: The prediction assumes similar training and conditions. If you're better at shorter/longer distances, adjust the exponent slightly (0.98-1.10).

Q5: Can I predict shorter distances from longer ones?
A: Yes, the formula works both ways, but predictions from longer to shorter distances tend to be less accurate.