Running Pace Calculator
Pace per mile and per km, speed, and predicted 5K, 10K, half, and marathon times.
Every calculation runs locally in your browser. Race predictions are a straight-line estimate from your pace — they don't account for fatigue over longer distances, so treat them as a rough guide, not a guarantee.
Pace per km
5:00 /km
Pace per mile
8:03 /mi
Speed
12 km/h
Speed
7.5 mph
Predicted race finish times
For informational and educational purposes only — not medical advice, and not a substitute for consulting a qualified professional about your specific situation. TrueMeasureKit is not liable for decisions made based on these results. See our Terms of Service.
Pace vs. speed — two views of the same effort
Runners typically think in pace — minutes per mile or per kilometer — because it's easy to check against a mile marker mid-run. Cyclists and race organizers more often use speed. Both describe the same effort; this calculator converts between them automatically, along with the other distance unit, so you're never stuck doing the mile-to-kilometer conversion by hand mid-workout.
Frequently asked questions
How are race time predictions calculated?
Using established endurance-performance formulas (like the Riegel formula) that extrapolate a predicted time at a different distance from a known pace or recent race result, accounting for the fact that pace naturally slows somewhat over longer distances.
How reliable are these race predictions?
They're a reasonable estimate assuming consistent training and similar conditions, but factors like terrain, weather, pacing strategy, and race-day fitness can meaningfully shift the actual result.