1. What is the 5k to Half Marathon Time Prediction?

This calculator predicts your half marathon time based on your 5k race time using a well-established formula that accounts for the non-linear relationship between distance and running performance.

2. How Does the Calculator Work?

The calculator uses the following formula:

Where:

• \( T1 \) — Your 5k time in hours (decimal)
• \( D1 \) — 5k distance (3.1 miles)
• \( D2 \) — Half marathon distance (13.1 miles)
• \( T2 \) — Predicted half marathon time

Explanation: The exponent of 1.06 accounts for the fact that running speed decreases slightly as distance increases, making the relationship non-linear.

3. Importance of Time Prediction

Details: Knowing your predicted half marathon time helps with race pacing, training plan development, and setting realistic goals based on your current fitness level.

4. Using the Calculator

Tips: Enter your best recent 5k time in hours, minutes, and seconds. The calculator works best with race times (not training runs) and assumes similar conditions for both races.

5. Frequently Asked Questions (FAQ)

Q1: How accurate is this prediction?
A: It's reasonably accurate for most runners, but individual variation exists based on training specificity, endurance, and race conditions.

Q2: Does this work for other distances?
A: Yes, the formula can be adapted for other distances by changing D1 and D2 values.

Q3: Why is the exponent 1.06?
A: Research shows this value best accounts for the non-linear decrease in speed with increasing distance for most runners.

Q4: Should I use my training 5k time?
A: For best results, use an actual race time where you ran all-out, as training runs may not reflect true performance.

Q5: How can I improve my half marathon time?
A: Focus on increasing weekly mileage, incorporating long runs, and doing specific tempo work at goal half marathon pace.