Running Pace Calculator
The complete running calculator — find your pace from a time and distance, predict race finish times, or work out how far you can run in a set time. Includes 5K to marathon projections.
Running Pace Guide
Pace vs Speed
Pace (min/km or min/mile) is how runners measure effort — lower numbers are faster. Speed (km/h or mph) is the physics definition. They're inversely related: 5:00/km = 12 km/h, 4:00/km = 15 km/h, 3:00/km = 20 km/h. Most GPS watches and running apps show pace; most treadmills show speed.
Race Time Predictions
Race predictions use the Riegel formula: T2 = T1 × (D2/D1)^1.06. The 1.06 exponent accounts for the fact that longer races are proportionally slower — you can't sustain 5K pace for a marathon. These predictions assume even fitness and race conditions. In practice, heat, hills, and fatigue introduce significant variation.
Training Paces by Zone
Easy / recovery runs: 60–70 seconds per km slower than 10K race pace. Long runs: 45–90 seconds slower than 10K pace. Threshold (lactate) pace: approximately 10K race pace. Intervals: 5K pace or faster. Running all your training at one pace is the most common training mistake — easy runs should genuinely feel easy.
Converting Between Treadmill Speed and Pace
UK treadmills show km/h; US treadmills show mph. To convert km/h to min/km: divide 60 by the speed. So 10 km/h = 6:00/km, 12 km/h = 5:00/km, 15 km/h = 4:00/km. 1 mph = 1.609 km/h. A 6 mph treadmill setting = 9.66 km/h = 6:13/km pace.
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