Running Pace Calculator
Calculate running pace, finish time, or distance. Includes training zones (easy, tempo, threshold, interval) and race predictions.
HEALTHCalculate your running pace, finish time, or distance. Includes training pace zones (easy, long run, marathon, threshold, intervals) and race-time predictions for 5K, 10K, half marathon, and marathon from one known result.
Pace = total time divided by total distance. Race predictions use Riegel's formula: T2 = T1 × (D2/D1)^1.06. Training paces derive from race pace: easy is +60-90 sec/mi slower than 5K, marathon pace is +60-75 sec/mi, threshold is +25-30 sec/mi, VO2max intervals are at 5K pace. 80% of weekly mileage should be easy; only 20% at threshold or harder.
Running Pace Calculator
Calculate your running pace, finish time, or distance. Includes training zones (easy, tempo, threshold, interval) and race-time predictions from one known result.
Training Pace Zones
How Running Pace Math Works
Pace = total time divided by total distance. If you run a 5K in 25:00, your pace is 25:00 ÷ 3.1 miles = 8:04/mi. Going the other way: total time = pace × distance. The classic prediction formula is Riegel's: T2 = T1 × (D2/D1)^1.06. A 25:00 5K predicts roughly 52:30 for a 10K (25:00 × 2^1.06).
Training paces are derived from race pace using Jack Daniels' VDOT system or McMillan tables. As a quick rule: easy = +60-90 sec/mi slower than 5K pace, marathon pace = 5K + 60-75 sec/mi, threshold = 5K + 25-30 sec/mi, VO2max intervals = 5K pace itself. 80% of weekly mileage should be easy; only 20% should be at threshold or harder.
Common race distances: 5K = 3.107 mi = 5000 m, 10K = 6.214 mi = 10,000 m, half marathon = 13.109 mi = 21,097 m, marathon = 26.219 mi = 42,195 m. For race-day pacing, run the first half slightly slower than goal pace (negative split) - the most common mistake is going out too fast and fading in the final third.
Pace predictions assume similar effort levels and trained runners. Race-day weather, course profile, and fitness specificity (5K speed vs marathon endurance) all shift actual times.