Nailing the Half Marathon
The half marathon (13.1 miles or 21.0975 kilometers) is the most popular long-distance race. It sits right in the sweet spot requiring speed from your 5K and 10K training, but demanding the aerobic endurance necessary to cross the threshold into long distance.
How to use this estimate
We use the Riegel formula to calculate your half marathon finish based on your 5K or 10K results. If your recent 10K was run confidently and you have maintained a strong weekly mileage base, this estimate will be highly accurate.
Once you've found your predicted Half Marathon finish time, plug it into our Running Pace Calculator & Split Generator to generate a split-by-split plan for race day.