Calculate running pace

Convert a distance and finish time into pace, speed, and constant-pace times for standard road-race distances.

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ToolRunning Pace Calculator
Input
Output
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Preview

How it works

Elapsed time becomes seconds and miles become kilometres at exactly 1.609344 km per mile. Dividing seconds by kilometres gives pace, taking its reciprocal gives speed, and multiplying by 5, 10, 21.0975, or 42.195 gives even-pace race times.

Formula
pace per kilometre = elapsed seconds ÷ kilometres
speed in km/h = 3,600 ÷ seconds per kilometre
  • Kilometres are the initial unit because every internal standard distance is metric.
  • Equivalent times deliberately preserve pace and are not race-performance predictions.

Worked example

A 45 minute 10K
Pace and equivalent finish times
Input
											Distance: 10
Unit: km
Time: 45:00
Output
												Pace per km: 4:30
Pace per mile: 7:15
Speed kmh: 13.33
Speed mph: 8.28
Five k: 22:30
Ten k: 45:00
Half marathon: 1:34:56
Marathon: 3:09:53

When to use this

Race plans turn 5K, 10K, half-marathon, and marathon goals into splits; treadmill sessions use the speed conversion, and training logs compare measured distance with elapsed time.

Edge cases

  • A time such as 10:99 is rejected because seconds and clock-style minutes must stay from 00 through 59.
  • A finish time of 00:00 is rejected before reciprocal speed can divide by zero.
  • Half-marathon and marathon equivalents hold the shorter-run pace constant and ignore fatigue, hills, wind, stops, and GPS distance error.

References