Pace Calculator
Convert between pace, speed, and finish time for any race distance.
Pace per kilometer
5:30 /km
Per mile
8:51 /mi
Speed
10.9 km/h
5K at this pace
27:30
10K at this pace
55:00
Pace, speed, and predictions
Pace is time per distance — the runner's native unit. Projecting a 5K pace onto a marathon is optimistic: each doubling of race distance typically slows pace by about 6% (Riegel's rule), so use projections as ceilings, not targets.
Training paces
Most training should run 60–90 seconds per km slower than race pace — easy running builds the aerobic base that race pace spends. If every run is at race effort, the race stops improving.
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