What pace do I need to run a sub-4 hour marathon?

You need to maintain a constant pace of 5:41 per kilometer or 9:09 per mile.

Is Riegel's formula accurate?

It is highly accurate for well-trained runners, but less so for beginners as it assumes consistent endurance across increasing distances.

Running Pace & Race Predictor

Calculate running pace, predict race finish times using Riegel's formula, and get 5K/10K splits.

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Documentation

Quick Summary: Running Pace & Race Predictor

To find your running pace in FY 2026-27, divide total duration by distance. Use Riegel's Formula [T2 = T1 * (D2/D1)^1.06] to predict your Half-Marathon or Marathon finish time based on your 5K or 10K performance.

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