Conquering the 13.1: Half Marathon Pacing Guides, Predictions, and Split Schedules
Master the half marathon with scientific pacing predictions, custom split tables, and Riegel formulas designed to optimize your 13.1-mile strategy.
The half marathon (13.1 miles or 21.0975 kilometers) has become the most popular road racing distance globally. It demands a sophisticated blend of raw speed, metabolic efficiency, and mental grit. Successfully pacing a half marathon requires understanding your lactate threshold and setting a realistic finish time goal based on recent athletic performances.
Using a half marathon calculator allows you to predict your finishing time by analyzing results from other race distances. It relies on the Peter Riegel equation to extrapolate your current speed, adjusting for aerobic endurance decay as the distance doubles.
The Importance of Negative Splits
Many elite runners advocate for running a "negative split"—meaning you run the second half of the race slightly faster than the first half. By calculating precise split milestones for 5K, 10K, and 15K, you can conserve key glycogen stores early in the race and finish with a strong, controlled kick.